With this work published in 1957, Gershom Scholem established the scientific foundation for the study of Jewish mysticism. Through a comprehensive analysis and interpretation of documents from the Jewish mystical tradition, this book provides a vivid picture of this intellectual historical period from its beginnings in late antiquity to the emergence of Hasidic sects in the 18th century. It also offers a wealth of biographical details about both well-known and lesser-known figures in the Jewish intellectual world. Scholem has scientifically illuminated texts that were long neglected or poorly interpreted and related them to the historical events. Thus, a compendium was created that conveys to the layperson the exciting image of a cultural and religious development that is an integral part of Western culture.