 The first section examines the origins and emergence of set theoretic mathematics around 1870; this is followed by a discussion of the period of expansion and consolidation of the theory up to 1900. Section 3 provides a look at the critical period in the decades 1897 to 1918, and Section 4 deals with the time from Zermelo to Gödel (from theory to metatheory), with special attention to the often overlooked, but crucial, descriptive set theory. 