Most of the early computers made by IBM for commercial production are briefly described with an emphasis on architecture and performance. The description covers a period offifteen years, starting with the design of an experimental machine in 1W9 and extending to, but not including, the announcement in 1964 of Systeml360. 701 clearly owed much to the machine at the Institute for Advanced Studies, to prior work at the University of Pennsylvania, and to Whirlwind at MIT; the 702 was largely stimulated by the Eckert-Mauchly UNIVAC; and the 650 had early roots in work at Engineering Research Associates. Cathode-ray tube (CRT) memory, as used in the 701 and 702, and index registers are well known to have originated at the University of Manchester. The names of J. P. Eckert and J. W. Mauchly, of J. von Neumann, who was a consultant on the 701, and of F. C. Williams readily come to mind. To give sufficient credit beyond the obvious, however, would go outside the scope of this paper.