This paper discusses ZBMs technical contributions to high level programming languages from the viewpoint of speciJic languages and their contributions to the technology. The philosophy used in this paper is that it is the appropriate collection of features in a language which generally makes the contribution to the technology, rather than an individual feature. Those ZBM languages deemed to have made major contributions are (in alphabetical order) APL, FORTRAN, GPSS, and PLII. Smaller contributions (because of lesser general usage) have been made by Commercial Translator, CPS, FOR-MAC, QUIKTRAN, and SCRATCHPAD. Major contributions were made in the area of formal definition of languages, through the introduction of BNF (Backus-Naur Form) for defining language syntax and VDL (Vienna Definition Language) for semantics. The definition of the term "programming language" has been unclear and controversial almost from the beginning of computer activity. In this paper, "programming Copyright 1981 by International Business Machines Corporation. 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. 520 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.