In this erudite and provocative new book Jonathan Brown has set out to compose ‘a sort of paean to an intellectual and religious tradition that nurtured a light of wisdom not only for its own adherents but for outsiders as well’. This is a bold ambition, for the tradition Brown comes to praise is that of the Sharia, specifically in its Sunni form. True, the vast and intricate body of jurisprudence, elaborated for well over a millennium by Muslim legal scholars – jurists and exegetes known as the ulama – offers much to admire. In its intellectual rigour, the subtlety of its logical distinctions, and its sheer ingenuity in making sense of often abstruse and contradictory premises, it does represent a formidable achievement. Even so, on the evidence Brown presents, often in great detail, the ‘light of wisdom’ – or even the lesser light of common sense – is not conspicuous among its offerings. There is a good reason for this. The Sharia draws on the allied sources of the Koran and the Traditions of the Prophet, those voluminous accounts of Muhammad’s words and deeds known as the hadith. These traditions are the basis of the Sunna, a code of comportment derived from Muhammad’s example that all right-thinking Muslims are enjoined to imitate. The ability to derive and to formulate valid legal rulings from this mass of material, much of it of dubious provenance, as well as from the frequently obscure verses of the Koran, constitutes a massive challenge. That the ulama succeeded in doing just this, amid great diversity of interpretative opinion and endless wrangling, stands as a tribute to their considerable exegetical sophistication as well as to their sheer tenacity.