Al Imam al Shafi'i's Risalah dominated studies in Islamic jurisprudence from the moment it appeared. Indeed, as a result of it, the scholars divided into two groups. One group, the majority of Ahl al Hadith, accepted it, and used it in support of al Shafi'i's school of legal thought. The other group, however, rejected most of what it contained, and attempted to refute whatever of al Imam al Shafi'i's work contradicted their own methods and practice before it had the chance to influence people. The members of this group were taken almost exclusively from the Ahl al Ra'i, all of whom were in complete disagreement with nearly all that al Imam al Shafi'i had written.
Ibn al Nadim mentioned books which were written in the field of Usul al Fiqh after the Risalah, including al Nasikh wa al Mansukh and al Sunnah by al Imam Ahmad ibn Hanbal (d 233 AH). Al Sunnah, however, is more a book on Tawhid and basic Islamic beliefs "Aqa'id" than of jurisprudence. There are two versions of this work in print; the longer version is the one printed in Makkah in 1349 AH, of which there are manuscript copies in the Dar al Kutub and Zahiriyyah libraries in Egypt and Damascus respectively. A smaller version, printed in Cairo without a date, deals with the fundamental beliefs of the Sunni Orthodoxy, or "Ahl al Sunnah".
Al Imam Ahmad also wrote Ta'at al Rasul "Obedience to the Messenger". Ibn Qayyim quotes from it often in his book, I'lam al Muwaqqi'in, and it seems that he possessed a copy of it. Nonetheless, I have looked for this book in many places, but have always been unable to find it. From the quoted passages in Ibn Qayyim's book, it is apparent that the book was indeed an important one on the subject of jurisprudence, and the methodology of dealing with the Sunnah. It may have been lost after Ibn Qayyim's time, or bound into another book, or the title page lost so that it may only be found after much searching.
The sources also mention that Dawud al Zahiri (d 270 AH) wrote al Ijma' "Consensus", Ibtal al Taqlid "On the Abolition of Imitation", Khabar al Wahid "On the Single-Individual Narration", al Khabar al Mujib "On the Obligating Narration", al Khusus wa al 'Umum "On the Particular and the General", al Mufassar wa al Mujmal "The Succinct and the Detailed", al Kafi fi Muqabalat al Muttalibi, i.e. al Imam al Shafi'i, "0n the Encounter with al Shafi'i", Mas'alatan Khalafa Fihima al Shafi'i "Two Issues on which He Differed with al Imam al Shafi'i".
During this period, the 'Ulama' who accepted the school of thought of al Imam Abu Hanifah devoted their attention to the study of Shafi'i's Risalah, both in order to refute what they disagreed with, and to derive their own source-methodology and principles of jurisprudence from the case law Fatawa of al Imam Abu Hanifah.
In this vein, the Hanafi scholars produced several works. 'Isa ibn Abban (d 220 Ah) wrote Khabar al Wahid, Ithbat al Qiyas, "Validating Analogical Deduction", and Ijtihad al Ra'i, "The Exercise of legal Reasoning".
Al Barza'i (d 317) wrote Masa'il al Khilaf "Issues of Disagreement", of which there is a 236-page copy in the Zaytunah Library in Tunis, number 1619.
Abu Ja'far al Tahawi (d 321) wrote Ikhtilaf al Fuqaha' "Disagreement of the Jurists", which was summarized by Abu Bakr al Jassas (d 37O). There is a copy of this hook in Cairo. For more details, refer to the Index of Ma'had al Makhtutat (1/329).55
Al Karabisi al Najafi (d 322) wrote al Furuq "Differences", of which there are manuscripts in the Ahmad III and Fayd Allah libraries in Istanbul.
Several untitled works on jurisprudence were also attributed to Ibn Sama'ah (d 233).56
Al Kannani (d 289) wrote al Hujjah fi al Radd 'Ala al Shafi'i, "The Evidence in Refutation of Imam Shafi'i".
'Ali ibn Musa al Qummi, the Hanafi (d 305) wrote Ma Khalafa Fihi al Shafi'i al 'Iraqiyin Fi Ahkam al Qur'an "Instances in which al Shafi'i Opposed the Iraqis in the Legal Interpretation of the Qur'an", Ithbat al Qiyas, al Ijtihad and Khabar al Wahid.
Abu al Hasan al Karkhi (d 340) wrote his well-known hook al Usul "The Sources", which was printed with a collection of other books in Cairo (no date).
Abu Sahl al Nawbakhti (d. circa 93 AH), who belonged to the Imamiyah, wrote Naqd Risalat al Shafi'i "A Critique of al Shafi'i's Risalah", Ibtal al Qiyas "Invalidating al Qiyas", and al Radd 'Ala Ibn al Rawandi Fi Ba'd Ara'ihi al Usuliyah ("Refutation of Certain of Ibn al Rawandi's Legal Opinions"). Ibn Junayd (d 347), who belonged to the Zaydiyyah group, wrote al Faskh 'Ala Man Ajaza al Naskh lima Tamma Shar'uhu wa Jalla Naf'uhu "The Nullification of those who Permitted Abrogation on Laws already Promulgated and Proved Beneficial", and al Ifham li Usul al Ahkam "Understanding Juristic Principles".
The adherents of al Imam al Shafi'i's school of legal thought produced the following works:-
Abu Thawr (d 240) wrote Ikhtilaf al Fuqaha' "Disagreement of the Jurists".
Abu 'Abd Allah Muhammad ibn Nasr al Marwazi (d 294) also wrote a book on the same subject.
Abu Abbas ibn Surayj (d 305) wrote a hook refuting both 'Isa ibn Abban and Muhammad ibn Dawud al Zahiri on matters in which they differed with al Imam al Shafi'i.
Ibrahim ibn Ahmad al Marwazi (d 340) wrote Al Umum wa al Khusus "The General and the Particular" and Al Fusul fi Ma'rifat al Usul57 "Chapters About Knowledge of Legal Source-Methodology".
Some of these scholars devoted their attention to producing commentaries on al Shafi'i's al Risalah; like Abu Bakr al Sayrafi (d 330), Abu al Walid al Nisaburi (d 365 or 363), Abu Bakr al Jawzaqi (d 388) and Abu Muhammad al Juwayni, the father of the famed Imam al Haramayn, teacher to al Imam al Ghazzali.
Commentaries on the Risalah are also attributed to five other scholars, namely: Abu Zayd al Jazuli, Yusuf ibn 'Umar, Jamal al Din al Afqahsi, Ibn Fakihani, and Abu al Qasim 'Isa ibn Naji. None of these commentaries, from which the scholars used to quote until after the seventh century, have come to light in modern times.
Shaykh Mustafa 'Abd al Razzaq58 mentioned that the public library in Paris held a copy of al Juwayni's commentary on the Risalah, and quoted some parts of it. I, myself, have tried to locate this manuscript in Paris; but failed. Perhaps it had been placed with other books under a different heading or title. Probably, the only way to find it is to sift through all the manuscripts. That, however, is a daunting task, as the researcher would need to spend a great deal of time on the undertaking.
What we have mentioned so far can hardly be regarded as development, as it mainly revolves around criticizing, supporting or commenting on the Risalah, and really goes no further than that. Once the discipline had been established, this state of affairs obtained until about the beginning of the fifth century AH, when what could be considered as significant development in the field began to take place.
During this period, al Qadi al Baqillani (d 402) and al Qadi 'Abd al Jabbar al Hamadani (d 415) undertook to re-write the whole subject of the practice and principles of Shari'ah Source Methodology, or al Usul.
In his book al Bahr, al Zarkashi wrote: "... the two judges, the Qadi of Ahl al Sunnah, Abu Bakr Tayyib al Baqillani, and the Qadi of the Mu'tazilah, 'Abd al Jabbar, came and expanded upon what had been written, clarified what had previously been little more than indications, provided detail to what had been mentioned in a general way, and removed ambiguities."
Al Qadi al Baqillani earned the title Shaykh al Usuliyyin59 "Master of the Scholars of al Usul", after he wrote al Taqrib wa al Irshad "Clarification and Guidance". This hook has been lost for centuries; though it may yet turn up in one collection of manuscripts or another. In any case, the scholars of al Usul continued quoting from it until the ninth century AH.
For his part, al Qadi 'Abd al Jabbar wrote a book entitled either al 'Ahd "The Covenant" or al 'Amad "The Pillars" and wrote his own commentary on it.
Imam al Haramayn (d 478 AH) summarized al Baqillani's al Taqrib wa al Irshad, in a book entitled al Talkhis "The Summarizing" or al Mulakhkhas "The Summary", of which some pages are preserved in some manuscript collections. Later scholars of jurisprudence transmitted many of al Baqillani's ideas from this work.
Imam al Haramayn patterned his own book on al Usul, al Burhan "The Proof", on al Baqillani's al Taqrib, in that it included all fields of jurisprudence, was free in its method, and followed whatever evidence was available.60 He disagreed with his teachers, al Imam al Ash'ari and al Imam al Shafi'i, on so many issues that many of his fellow scholars from the al Shafi'i school of legal thought rejected his commentary and did not give it the attention it deserved, even though they transmitted a great deal from it in their own books.
Two Maliki scholars, al Imam Abu 'Abd Allah al Maziri (d 536 AH) and Abu al Hasan al Abyari (d 616), wrote commentaries on al Burhan; and a third Maliki scholar, Abu Yahya, combined the two commentaries. Still, all three of these scholars dealt harshly, if not somewhat unfairly, with Imam al Haramayn because of what they considered to be his audacity in refuting al Imam al Ash'ari on matters where he disagreed with him, and in refuting al Imam Malik on the question of al Masalih al Mursalah. Imam al Haramayn added introductions to al Imam al Shafi'i's book which dealt with matters not found in the Risalah. He began by discussing the knowledge of those sources and concepts which anyone who wishes to study any science in depth must have. He explained that the sources of Usul al Fiqh were 'Ilm al Kalam "Scholastic Theology", Arabic language and Fiqh. Then he dealt with legal judgements, duties, and competence, discussing in detail issues pertaining to various sciences, and explaining those which could be understood by reason, and which by religion. All the above matters formed an introduction to a discussion of the term al Bayan, "perspicuous declaration", the subject with which al Imam al Shafi'i began the Risalah.
It is quite apparent, however, when we see how Imam al Haramayn dealt with the subject of al Bayan, and with other of the subjects mentioned in the Risalah, that Imam al Haramayn defined the terms, including al Bayan, more precisely than al Imam al Shafi'i had done. He defined it, explained its essence, mentioned disagreements concerning it, and set forth its different categories. He also dealt with another matter which al Imam al Shafi'i had not dealt with, Ta'khir al Bayan ila Waqt al Hajah "Deferment of al Bayan until the time when it is Needed", and disagreements concerning it. Then, in discussing the different categories of al Bayan, he reiterated the five categories which al Imam al Shafi'i had mentioned, advocated Abu Bakr Dawud al Zahiri's comments on the subject, and then mentioned the other categories of al Bayan which some jurists had suggested.
Imam al Haramayn held the opinion that al Bayan meant "evidence", of which there are two types: 'Aqli "rational" and Sam'i "received". The basis for "received" evidence is the miraculous Qur'an; so that the closer the evidence is to the Qur'an, the more precedence it has. Hence the order of priority in "received" evidence is: the Qur'an, the Sunnah, al Ijma' Khabar al Wahid, al Qiyas.
Then he dealt with languages, and explained that the scholars of jurisprudence have dealt with linguistic matters which the scholars of Arabic had omitted, such as Awamir "commands"; Nawahi "prohibitions", and al 'Umum wa al Khusus "the General and the Specific" which Imam al Shafi'i had dealt with.
In the course of this linguistic discussion, he mentioned some of al Baqillani's ideas, which clearly indicates that al Baqillani had already made these additions to al Imam al Shafi'i's methods.
When al Imam al Ghazzali was the student of Imam al Haramayn it was only natural that he be influenced by him. In fact, al Imam al Ghazzali wrote four books on the subject of al Usul. The first of these works was al Mankhul "The Sifted", a medium-sized volume written as though for beginners or intermediate level students of al Usul. Of the second book nothing is known except that it was referred to in al Mustasfa61, and that its title was Tahdhib al Usul "On the Refinement of Usul". The third book is entitled Shifa' 'al Ghalil fi Bayan al Shibh wa al Mukhayyal wa Masalik al Ta'lil, and was edited and published in Baghdad in 1390/1971. Al Imam al Ghazzali's Encyclopedia of Shariah Source Methodology, his fourth book on the subject, and his last word, was al Mustasfa, which has been printed several times in Egypt and elsewhere. Indeed, this is the work he wrote after coming out of his period of meditation and seclusion62.
Al Imam al Ghazzali began his book with an introduction in which he covered nearly all of Aristotelian logic, a subject in which he had always been deeply interested. Then he wrote about the Hadd "Prescribed Punishment", about the conditions that must be satisfied before it can be applied, and about the different types of Hudud. He then discussed the Dalil "Evidence" and its various types.
At this point in the book, al Imam al Ghazzali proceeds to discuss the four poles of his work, headings under which everything in the field of al Usul is covered, and which his teacher, Imam al Haramayn, and predecessors, such as al Baqilani, were most concerned with. As his teacher had his own opinions that differed from those of al Imams al Shafi'i and al Ash'ari, so also did al Imam al Ghazzali hold opinions which differed from those of his predecessors. Likewise, among al Imam al Ghazzali's contemporaries there were those who accepted his views and those who did not.
These were the most important developments made by the followers of al Imam al Shafi'i in the field of Usul.
The second group to contribute to the development of the discipline were the Mu'tazilah. After al Qadi Abd al Jabbar had written his book, al Amad or al 'Ahd, and written a full commentary on it, he recorded some of his opinions on al Usul in his encyclopedia, some parts of which have been found and printed under the title al Mughni. The seventeenth volume of this encyclopedia was devoted to studies in al Usul.
As Imam al Haramayn concerned himself with the book of al Baqillani, so Abu al Husayn al Basri al Mu'taziuli (d 435 AH) concerned himself with the books of al Qadi 'Abd al Jabbar, and wrote a commentary on al Amad/al 'Ahd. When he felt that this commentary was too long, he summarized it in his well-known book al Mu'tamad "The Reliable", which is in print and widely available.
During this period, al Shaykh Abu Ishaq al Shirazi (d 476 AH) wrote his two books. al Lam' "The Bright Light" and al Tabsirah "Enlightenment", both of which are in print.
Al Qadi Abu Yahya al Farra' al Hanbali wrote a book on Usul entitled al 'Uddah fi Usul al Fiqh "The Tools of Usul al Fiqh", which was edited and published in Saudi Arabia in 1400/1980.
Ibn 'Aqil al Baghdadi, another Hanbali scholar, wrote al Wadih Fi al Usul "What is Clear in Usul".
Abu al Khattab wrote his well-known book, al Tamhid "The Preface", which was recently edited and published in Makkah.
Among the books written by scholars of the Maliki school of legal thought at that time was 'Uyun al Adillah Fi Masa'il al Khilaf Bayna Fuqaha' al Amsar "Profusion of Evidence or Controversial Issues Among the Jurists of the New Muslim Settlements", by Ibn al Qassar al Baghdadi (d 398 AH), of which there is a copy at Qarawiyin University in Fez.63 Al Shirazi considered this to be the best book by any Maliki scholar on the subject of juristic differences. Ibn al Qassar also wrote Muqaddimah fi Usul al Fiqh "Introduction to Usul al Fiqh", of which there is a copy at the Azhar University library.
The books of the Shafi'iyah, Hanabilah, Malikiyah and Mu'tazilah all followed a similar pattern in the order of their chapters and the treatment of their subject matter. Eventually, this pattern became known as "the method of the Mutakallimun."
Some historians of Usul al Fiqh have suggested that al Qadi Abu Yusuf and Muhammad ibn al Hasan wrote about jurisprudence,64 but this claim has not been proven.
The author of Kashf al Zunun65 quoted 'Ala' al Din's saying from Mizan al Usul "Usul in the Balance":
"Know that Usul al Fiqh is a branch of Usul al Din; and that the composition of any book must of necessity be influenced by the author's beliefs. Therefore, as most of the writers on Usul al Fiqh belong to the Mu'tazilah who differ from us in basic principles, or to Ahl al Hadith who differ from us in questions of detail, we cannot rely on their books.
Our (Hanafi) scholars' books, however, are of two types. The first type is of books that were written in a very precise fashion, because their authors knew both the principles and their application. Examples of this type are: Ma'khadh al Shar' "The Approach of the Shari'ah" and al Jadal "Argument" by Abu Mansur al Maturidi (d 333 AH).
"The second type of book dealt very carefully with the meanings of words and were well-arranged, owing to the concern of their authors with deriving detailed solutions from the explicit meanings of narrations. They were not, however, skillful in dealing with the finer points of al Usul or questions of pure reason. The result was that the writers of the second type produced opinions in some cases agreeing with those with whom we differed. Yet, books of the first type lost currency either because they were difficult to understand or because scholars lacked the resolution to undertake such works."
There is much that could be said about how accurately this statement depicts the development of Hanafi studies of al Usul, even if it was made by a Hanafi. The statement does, nonetheless, come close to reality in explaining the role of the Hanafi yah in the development of Usul al Fiqh. In the first period, these scholars concentrated, even before al Imam al Maturidi, on discussing the issues brought up by al Imam al Shafi'i in his Risalah, as 'Isa ibn Abban and others did.
During the following period, one of the most prominent writers of al Usul was Abu al Hasan al Karkhi (d 340 AH). His book on al Usul consists of a limited number of pages that were printed with Abu Zayd al Dabusi's book, Ta'sis al Nazar "Establishing Opinion", which has been published in several editions in Cairo.
Then, Abu Bakr al Jassas (d 370 AH) wrote his work, Al Fusul Fi al Usul as an introduction to his Ahkam al Qur'an "Legal Interpretations of the Qur'an"66. Al Fusul has been researched and edited for a doctoral thesis, and was published recently in Kuwait.
True development of the Hanafiyah writing on the subject of al Usul. may be considered to have begun with al Imam Abu Zayd al Dabusi (d 340) who wrote two important books on the subject: Taqwim al Adillah "Appraising Evidence", all or some of which has been researched and edited, but which has not yet been printed, and Ta'sis al Nazar67. Abu Zayd made use of the work on al Usul done by his predecessors, especially that of Al Karkhi and Al Jassas, but with the difference that he expanded the field and explained it in greater detail; he also made brief reference to the points on which the Hanafiyah agreed and disagreed with others on matters of Usul.
Abu Zayd was followed by Fakhr al Islam al Bazdawi (d 482), who wrote the well-known Kanz al Wusul Ila Ma'rifat al Usul "A Treasury On Attaining Knowledge of the Usul", in which he dealt with Usul in general. Later Hanafiyah scholars took great interest in the book and wrote many commentaries on it; the best and most important of which was Kashf al Asrar "Secrets Uncovered" by 'Abd al Aziz al Bukhari (d 830). This commentary has been published in several editions in both Istanbul and Egypt.
Likewise, Shams al A'immah al Sarkhasi (d 423 AH) wrote Usul al Sarkhasi, which has been printed in two volumes in Egypt. This book is considered to be in many ways an alternate reading of al Dabusi's Taqwim al Adillah. The Hanafiyah scholars of al Usul took great interest in the books of al Bazdawi and al Sarkhasi, and concerned themselves with teaching and commenting upon them for a long time.
From the above it should be clear that the development of Usul al Fiqh, as a specialized discipline, had been completed, and that its issues and academic parameters had been defined by the fifth century AH. Indeed, by that century, the scholars of every school of legal thought had recorded their own interpretations and understanding of Usul al Fiqh.
Writings on the subject of al Usul generally followed one of two methods. The first was al Shafi'i's method, or the method of the Mutakallimun. This was the method followed by the Shafi'iyah, the Malikiyah, Hanabilah and the Mu'tazilah68, and it was known as the "method of the Mutakallimun" because the authors of books written according to this method used to introduce them with discussions of theological and philosophical issues, such as al Hasan and al Qabih "The Good and the Reprehensible', Hukm al Ashya' Qabl al Shar' "The Legal Status of Matters Prior to the Revelation of Shari'ah", Shukr al Mun'im "The Necessity of Gratitude to the Bestower", and al Hakim "The Possessor of Sovereignty". A further reason for its being labeled "the method of the Mutakallimun" was the use of the deductive method in defining the principles of source methodology, in ascertaining the validity of those principles, and in refuting those whose opinions differed without paying much attention to the issues and details which stem from the application of these principles.
The Hanafi method of writing on al Usul involved defining the principles of Usul from the details of legal issues with which their earliest predecessors had already dealt. Thus, the basis for their studies of al Usul was derived from the details of previously settled legal issues, and not the other way round. Therefore, one who studies Usul al Fiqh according to this method will gather the details of issues concerning which the Hanafi Imams have already given Fatawa, and then analyze them. Through his analysis he will decide the basis on which these Fatawa were given.
Shah Wali Allah of Delhi commented:
"I found that some of them claimed the differences between Abu Hanifah and al Shafi'i were founded on the Usul mentioned in al Bazdawi's book and elsewhere. But the truth is that most of these Usul were themselves derived from the differing legal pronouncement of the Imams. My opinion of the matter is that such principles of al Usul as the rules which say that the specific "al Khass" is obvious "Mubayyan", and does not need to be followed by a declaration "Bayan"; that the addition of details to a text constitutes abrogation "Naskh"; that the comprehensive "al 'Amm" is definitive "Qat'i" like the specific "al Khass"; that mere numbers of narrations may not be taken as a factor in according preference Tarjih to one opinion or another; that the Hadith of one who is not a Faqih need not necessarily be adopted in cases where there can be no resort to reason; that there is no legitimacy to the notion of progressing from a precondition "Shart" or description "Wasf" to a legal deduction; that the imperative "al Amr" in a text always indicates legal obligation "Wujub"; and so on, all of these are examples of principles inferred from the judgements of the Imams. Indeed, there are no sound narrations to suggest that Abu Hanifah or his two companions, Muhammad and Abu Yusuf, adhered to any of these principles of source methodology. As such, then, these principles deserve no more to be preserved and defended, as al Bazdawi and the others did, than the opposing principles do."69
Following the consolidation of the subject matter of this discipline, according to the method of the Mutakallimun, in four major works: al 'Ahd, al Mu'tamad, al Burhan and al Mustasfa, two great scholars from among the Mutakallimun summarized these four books in works of their own.
The first was al Imam Fakhr al Din al Razi (d 606 AH), who summarized them in his book al Mahsul "The Sum and Substance", which I had the honour of researching and editing. This work has been printed in six volumes by Imam Muhammad ibn Sa'ud University, and is now being reprinted.
The second was al Imam Sayf al Din al Amidi (d 631 AH), who summarized these four books in his al Ihkam Fi Usul al Ahkam "Precision in the Source Methodology of Law", which has been published in Riyadh, Cairo and elsewhere.
These two books are lengthier and certainly easier to read and understand than others. Of the two, al Mahsul is written in clearer language, and is more detailed in its explanations. Many glosses and commentaries have been written on these two books. Taj al Din al Armawi (d 656) summarized al Mahsul in his book al Hasil "The Outcome", which was researched and edited for a doctoral thesis at al Azhar University, but has not yet been published.
Al Imam al Razi himself also summarized it in a book entitled al Muntakhab "Selections", which one scholar has researched and edited.
Al Qadi al Baydawi (d 685) summarized al Hasil in his book Minhaj al Wusul Ila 'Ilm al Usul "The Way of Mastering the Science of Source Methodology"; but his summary was so abbreviated that the result is like a riddle, very difficult to understand. Thus, many scholars undertook to produce commentaries on the book. Among such commentaries, the best is that of al Isnawi (d 772), which is entitled Nihayat al Su'l "An End to Questioning" This book occupied the attention of the scholars in the field for a long time, and the Shafi'iyah scholars al Al Azhar are still devoted to it.
Al Amidi's book, al Ihkam "Precision" was summarized by Ibn al Hajib (d 646) of the Maliki legal school in his book Muntaha al Su'l wa al Aml Fi 'Ilmay al Usul wa al Jadal "The Ultimate in the Sciences of Jurisprudence and Argumentation", which is well-known among the followers of al Imam Malik.
The best available commentary on this work is that of 'Udad al Din (d 756), for which several glosses and commentaries have been written.
All of these books were written following the method of the Mutakallimun, defining the principles, basing evidence upon them, and seeking to refute by means of these those who held opposing views, until one of the two groups admitted defeat.
The Hanafiyah scholars of al Usul were likewise occupied in studying the books of al Bazdawi and al Sarkhasi. This situation remained the same until the end of the sixth century and the beginning of the seventh century AH, when the scholars of at Usul began using a new method. This method involved combining the methods of the Mutakallimun and the Hanafiyah scholars so as to produce books which combined the Usul of the two groups.
Following this method, Muzaffar al Din al Sa'ati (d 694) wrote Bad'i al Nizam al Jam'i Bayna Kitabay al Bazdawi wa al Ihkam. This book is one which is readily available in print.
Sadr al Shari'ah (d 747) wrote Tanqih al Usul "Refining al Usul", in which he summarized al Mahsul, Usul al Bazdawi and Mukhtasar ibn al Hajib. He then wrote a commentary on his own book entitled al Tawdih "Clarification", to which al Taftazani (d 792) added a marginal commentary entitled al Talwih. All three books, al Tanqih, al Tawdih and al Talwih are available in print.
Among the Shafi'iyah scholars, Taj al Din al Subki wrote his famous book, Jam' al Jawami' "The Compilation of the Comprehensive". In the introduction, he mentioned that he had compiled his work from one hundred different books on al Usul. Many scholars wrote commentaries and added footnotes to al Subki's book. Of these, perhaps the most important and most widely-available commentary is Sharh al Jalal al Muhalli, which remains even today the basis for studies in al Usul, especially for the Shafi'iyah scholars.
Badr al Din al Zarkashi (d 794) also wrote a commentary, entitled Tashnif al Masami' "To Please the Ears", part of which was printed in Cairo with footnotes by al Shaykh al Muti'i (d 1354). One of the students at Imam Muhammad ibn Sa'ud University has researched and edited part of this book recently for his doctoral thesis.
Al Zarkashi also wrote al Bahr al Muhit "The Vast Ocean", in which he collected the submissions of scholars of al Usul from over one hundred books. A student has stared to research and edit this book, under our supervision, for his doctoral thesis, and has already completed one volume and made it ready for publication.
Among the Hanabilah, Ibn Qudamah (d 620) wrote Rawdat al Nazir wa Jannat al Manazir, in which he summarized al Ghazzali's al Mustasfa, and added to it other useful material on matters in which the Hanabilah disagreed with others. This book has been printed several times, and the Hanabilah took great interest in it, to the extent that they ignored nearly all other books.
Sulayman al Tufi (d 716) summarized this work, and then commented upon his summary in two volumes.
Among the Malikiyah, al Qarrafi (d 684) wrote Tanqih al Fusul fi Ikhtisar al Mahsul "Refining Chapters in Summary of the Mahsul". Al Qarrafi also wrote a commentary on al Mahsul in a large volume entitled Nafa'is al Usul "Treasures of the Usul", part of which has been researched and edited under our supervision in Riyadh.