Muhammad ibn Yazid, known by his father's byname as Ibn Majah, was born in 824 CE in Qazwin in northern Iran and made the customary journeys of a traditionist, hearing masters in Rayy, Basra, Kufa, Baghdad, Syria, Egypt and the Hijaz. Besides the Sunan he composed a Quran commentary and a history of Qazwin's transmitters, both now known only in fragments and citations; he died in 887 CE.
The Sunan is his monument. It arranges roughly 4,300 traditions, in the standard printed numbering 4,341, into books following the sequence of jurisprudence from purification and prayer through marriage, commerce, medicine, dream interpretation and tribulations, and its chaptering was admired as unusually systematic, a clean map of the law's topics. Where the other Sunan compilers annotate their materials, Ibn Majah is spare, rarely passing verdicts, which left the grading of his reports to later specialists; the standard editions carry the assessments of scholars such as al-Busiri on the traditions unique to him. The book's zawaid have kept it indispensable: for many rulings and devotional practices it is the only canonical source, and the collection preserves early material on subjects, such as medicine and the trials of the last days, that the stricter books admit more narrowly. Read with its criticism attached, as the tradition itself insists, it completes the canon precisely by being its widest door.