The paper describes salient architectural features of the Intel iAPX 432, a recent innovative microprocessor design. It is intended as a companion to a recently published paper (Witten, 1981) which surveys the architectures of the new generation of 16-bit microprocessors, but which was written prior to the announcement of the iAPX 432. The novelty of the new processor lies chiefly in its sophisticated segmentation structure and the design of its instruction set; these are covered in a tutorial fashion and related to earlier developments in computer architecture