Back in 1993, as senior librarian at the Vernadsky Library in Kiev, Ukraine, in charge of cataloguing a newly uncovered Judaica collection, I came across an enigmatic manuscript entitled Sefer ha-ḥeshek. It did not match the bulk of the Judaica holdings. Nor did it fit in Abraham Harkavy's collection of medieval manuscripts. It was too Ashkenazic for Abraham Firkovich's Karaite papers, and too early for most of S. Ansky's nineteenth-century folkloric materials. The manuscript had a wooden cover, separate from the text, with a copper monogram Sefer ha-ḥeshek in Hebrew (hereafter—SH). SH's title appears randomly as a running head; the author occasionally refers to the title of the manuscript. Primarily because of its size—411 folios, 23 of them blank, some 760 filled pages altogether—and due to its magical contents, I discarded any attempts to identify the manuscript as a version of the well-known Sefer ha-ḥeshek, a twenty-or-so-page kabbalistic treatise on the names of the archangel Metatron attributed to Isaac Luria. Also, since the manuscript is not a commentary on the book of Isaiah or Proverbs, it could neither be Solomon Duran's nor Solomon ha-Levi's Ḥ eshek shelomoh.