What scholars have always admired in Sahih Muslim is its arrangement. Where al-Bukhari repeats a tradition wherever it serves a legal heading, cutting and re-citing it under many chapters, Muslim brings every version of a tradition together in one place: the report is given with its strongest chain, then the variant chains and differences of wording follow in sequence, so the reader can see at a glance how the tradition travelled and where its tellings diverge. The book opens with an introduction unique among the six collections, in which Muslim sets out the duty of transmitting only from reliable narrators, attacks the careless and the fabricators, and debates a technical question of chains with unnamed contemporaries, giving posterity a window into the criticism of his day in the critic's own voice. The collection contains roughly three thousand distinct traditions, and about 7,500 numbered reports when the variant tellings are counted.
Muslim ibn al-Hajjaj gathered them, tradition says, from a sifting of some three hundred thousand, over journeys that took him from his native Nishapur to the Hijaz, Iraq, Syria and Egypt, and he composed the book in his home city, reading it to students in the years before his death in 875 CE. Within the two Sahihs, most later scholarship ranked al-Bukhari's soundness fractionally higher and Muslim's organisation finer, a division of honours that has never really been revised.