This is a brief and lively introduction to the religious institutions, beliefs and practices of the Graeco-Roman world during the `Hellenistic Age' (c.300 BC-300 AD). Discussion of the various phenomena of Hellenistic religion is organized around the three classic types: piety, mystery, and gnosis. As the author follows the historical development of these phenomena, he demonstrates the effect of religion on two fundamental transformations of the Hellenistic world-view. The first of these is the transformation of the understanding of the structure of the cosmos from the archaic to the `Ptolemaic' view. The second transformation is what Martin describes as a shift in the relative importance of masculine and feminine god-images. He concludes with a discussion of late Hellenistic religion's interaction with and influence on early Christianity.