Since the 1990s, Early Modern and Medieval Science in Jewish sources has been actively studied, but the consensus was that no real scientific themes could be found in earlier Judaism. This book points them out in detail, and posits a new field of research: the scientific activity evident in the Dead Sea Scrolls and Early Jewish Pseudepigrapha. The publication of new texts and new analyses of older ones reveals crucial elements that are best illuminated by the history of science, and may have interesting consequences for it. The book attempts to account for scientific themes in Second Temple Judaism. It investigates the meaning and purpose of scientific explorations in an apocalyptic setting. An appreciation of these topics paves the way to a renewed understanding of the scientific fragments scattered throughout rabbinic literature. The book first places the Jewish material in the ancient context of the Near Eastern and Hellenistic worlds. While the Jewish texts were not on the cutting edge of scientific discovery, they find a meaningful place in the history of science, between Babylonia and Egypt, in the time period between Hipparchus and Ptolemy. The book uses recent advances in method to examine the contacts and networks of Jewish scholars in their ancient setting. Second, the book tackles the problematic concept of a national scientific tradition. It explores the tension between the hegemony of central scientific traditions and local scientific enterprises.