For all Muslims the Qurʾan is the word of God. In the first centuries of Islam, however, many individuals and groups, and some Shiʿis, believed that the generally accepted text of the Qurʾan is corrupt. The Shiʿis asserted that redactors had altered or deleted among other things all passages that supported the rights of ʿAli and his successors or that condemned his enemies. One of the fullest lists of these alleged changes and of other variant readings is to be found in the work of al-Sayyārī (3rd/9th century), which is indeed among the earliest Shiʿi...