Beginning in the eighth century, Islamic alchemy was strongly influenced by writings that passed under the name of Jabir ibn Hayyan (ca. 721–ca. 800): “Geber” as he came later to be known in the Latin West. Like Khalid, Jabir was instrumental in preserving alchemy's Greek heritage and transmitting it to Islamic culture; he is also believed to have written texts in Arabic on a wide range of subjects: mathematics and geometry, magic squares, astrology, medicine, military science, as well as alchemy. Problems of attribution, however, are especially acute in the case of Jabir, and it is now accepted that many works once regarded as his were actually fathered upon him by writers of the Isma'ilite sect in the tenth century (Plessner, Jabir, DSB; Holmyard 72–3). It is also common practice to distinguish between this earlier, Greek-inspired Arabic body of writings, the Corpus Jabirianum, and the highly influential body of Latin writings that appeared falsely under the name of “Geber” in the thirteenth and fourteenth centuries. This latter group includes such well-known works as the Summa perfectionis magisterii, Liber de investigatione perfectionis, Liber de inventione veritatis, Liber fornacum, and the Testamentum Geberi. Selections presented in this collection are drawn from the Latin writings and treat topics for which “Geber” achieved fame among medieval and Renaissance alchemists: the sulphur-mercury theory; the major processes in the preparation of the Stone (sublimation, descension, distillation, calcination, solution, coagulation, fixation, and ceration); furnaces and the “degrees” of fire; and other types of laboratory equipment.