Ahmad Hasan represents a scholarly tradition in Islamic jurisprudence that combines the philological rigour of classical Arabic source criticism with the analytical frameworks of modern legal and historical scholarship. His academic career was shaped by his long association with the Islamic Research Institute ? an institution committed, as he describes in the Preface to this work, to producing authoritative scholarly contributions across the principal domains of Islamic studies. It was within this institutional framework that Hasan undertook the research for The Doctrine of Ijma in Islam, working from the institute's holdings supplemented by the library collections of Lahore and Karachi.

His intellectual formation is visible in the architecture of the present study. Where an earlier generation of Western scholars ? represented here primarily by Joseph Schacht's The Origins of Muhammadan Jurisprudence ? had explored the early phase of ijma's development, Hasan took as his specific province the classical and post-classical periods: the elaboration of ijma's theoretical structure in the works of the major Sunni usulis from the fourth century of the Hijrah onward, and the doctrine's contested engagement with the conditions of modernity. His earlier monograph, The Early Development of Islamic Jurisprudence (Lahore, 1970), already demonstrated his command of the primary Arabic sources and his ability to situate juridical debates within the broader social and political history of the Muslim community.

What distinguishes Hasan's method in the present work is the combination of breadth and precision. He does not merely survey the opinions of the classical jurists on questions of competence, silence, and subject matter; he reconstructs the internal logic of their arguments, traces the trajectories of development between key thinkers ? al-Shafi'i, al-Jassas, al-Ghazali, al-Amidi, al-Juwayni ? and subjects those arguments to sustained critical evaluation. The comparative chapter on Sangha, Sanhedrin, and Church reflects his willingness to situate Islamic institutions within a genuinely comparative history of religious thought.

Hasan is equally at home with the modern reformist tradition. His treatment of Shah Wali Allah, Sayyid Ahmad Khan, Ubayd Allah Sindhi, Muhammad Iqbal, Mufti Muhammad Abduh, and Ziya Gokalp is neither apologetic nor dismissive. He takes seriously the intellectual challenges each thinker poses to the classical theory while remaining alert to the tensions ? historical, theological, and practical ? within their proposed reformulations. In this, he reflects a generation of Islamic scholarship capable of holding together the demands of traditional learning and the questions of a changed world.

The Doctrine of Ijma in Islam was prepared as part of the Islamic Research Institute's systematic programme of scholarly publication. It stands as Hasan's most sustained contribution to the academic study of Islamic legal theory and remains the standard English-language treatment of this foundational doctrine.