This volume provides a new interpretation of the functions of “mystery” language and secrecy in the Qumran scrolls. The texts preserved and composed at Qumran by the apocalyptic group known as the Yaḥad display an interest in revelation, interpretation, and ritual practice, and attest to the active cultivation of esoteric arts such as astrology and astronomy, physiognomy, and therapeutic “magic.” Much like its Babylonian priestly-scribal counterparts, the Yaḥad fostered and guarded its “mysteries”—its store of special knowledge available only to the elect—and used “mystery” terminology (especially raz) to claim authority and to erect social boundaries around themselves as the “men of the vision” and the “house of holiness.” The “Mysteries” of Qumran offers an in-depth semantic analysis of relevant terminology and integrates social-scientific and intellectual-history approaches in focusing on an important motif in the Dead Sea Scrolls.