A manuscript at the Jewish Theological Seminary of America contains the first five chapters of a ten-chapter Hebrew treatise on alchemy. Although Joseph Solomon Delmedigo (1591–1655) is named as the author, the treatise’s intimate connection with Arabic sources, especially the later Islamic alchemy associated with the work of Aydamar al-Jildakī, raise serious doubts about the attribution. The argument is made that even though Delmedigo could indeed have mastered Arabic, the ascription remains questionable. Highlights of the tract are presented. Publication of the text, with English translation and notes, is planned for some future date.