Neo-Mandaic is the last phase of a pre-modern vernacular closely related to Classical Mandaic, a Mesopotamian Aramaic idiom of Late Antiquity. This unique language is critically endangered, being spoken by a few hundred adherents of Mandaeism, the only gnostic religion to have survived until the present day. All other Mandaeans, numbering several tens of thousands, are Arabic or Persian speakers. The present study concerns the least known aspect of the language, namely its lexicon as reflected in both its dialects, those of the cities of Ahvaz and Khorramshahr in the Iranian province of Khuzestan. Apart from lexicological and etymological studies in Neo-Mandaic itself, the book discusses the contribution of the Neo-Mandaic lexis to our knowledge of literary Mandaic as well as aspects of this lexis within the framework of Neo-Aramaic as a whole.