Work on semiconductor physics, devices, and materials science carried on at IBM in the last twenty-five years is reviewed. Topics covered include hot electrons, inversion layers, the injection laser, electroluminescence, the Gunn effect, MESFETs, solar cells, superlattices, and amorphous materials and effects.The earliest IBM work was devoted to the theory of transport properties, primarily the Hall effect, and to the study of electron states. One significant early result was obtained by J. A. Swanson [2], who showed that the wellknown result for the saturation Hall constant R. (the Copyright IWl by International Business Machines Coiporation. Copying is permitted without payment of royalty provided that (1) each reproduction is done without alteration and (2) the Journal reference and IBM copyright notice are included on the first page. The title and abstract may be used without further permission in computer-based and other information-service systems. Permission to republish other excerpts should be obtained from the Editor. 779