Books by the real Jabir Ibn Hayyan had been translated into Latin during the 11th to 13th centuries, and had made a profound impression on European alchemists. Pseudo-Geber probably adopted the name of his illustrious predecessor in order to capitalize on his reputation. Pseudo-Geber's work also reflects 14th century European alchemical practices alongside earlier Arab ones.
Five of his works have survived, dated from about 1310:
Summa perfectionis magisterii ("The Height of the Perfection of Mastery"). William R. Newman, The Summa Perfectionis of Pseudo-Geber. A Critical Edition, Translation and Study, Leyde : E. J. Brill, 1991 (Collection de travaux de l'Académie Internationale d'Histoire des Sciences, 35).
Liber fornacum ("Book of Stills"),
De investigatione perfectionis ("On the Investigation of Perfection"), and
De inventione veritatis ("On the Discovery of Truth").
Testamentum gerberi
Being the clearest expression of alchemical theory and laboratory directions available until then — in a field where mysticism, secrecy, and obscurity were the usual rule — Pseudo-Geber's books were widely read and extremely influential among European alchemists.
Pseudo-Geber was instrumental in spreading Islamic alchemical theories throughout western Europe. He assumed that all metals are composed of sulfur and mercury and gave detailed descriptions of metallic properties in those terms. He also explained the use of an elixir in transmuting base metals into gold (see philosopher's stone).
Pseudo-Geber's rational approach, however, did much to give alchemy a firm and respectable position in Europe. His practical directions for laboratory procedures were so clear that it is obvious he was familiar with many chemical operations.
