The late Shlomo Pines (1908-1990) was this centurys outstanding historian of Islamic philosophy and science. This volume offers, for the first time in English. Pines doctoral dissertation on Islamic atomism; the German version appeared in 1936. Pines presents the atomic theories of matter, time and space, as they are found in the literature of kalam, as well their exposition in the writings of Abu Bakr al-Râzî; and then investigates in detail possible sources in the Greek, Indian, and other traditions. The present publication incorporates a few revisions which Pines himself had made in a draft translation. A number of the texts, which Pines consulted in the manuscript, have since been published, and some important studies on the kalam have appeared. Nonetheless, it can be stated in confidence that, sixty years after its first publication, Pines monograph is till today the most significant work on the subject.