The article deals with one of the most influential medieval Muslim polemical tracts against Judaism penned by Samau’al al-Maghribi (ca. 1130–1175), a Jewish convert to Islam. His work contains a tract against the Jews and an autobiography, including an account of visions of the Prophet Samuel and the founder of Islam. In his writing he covers full line of medieval controversy with Judaism: abrogation (naskh), distortion or forgery in Scripture (tahríf), anthropomorphism (tajsím), preserved annunciations of Islam and its prophet (aclám). The autobiography presents the author as a rationalist.