This paper establishes the roots of computers and automated teaching in the field of psychology and describes Dr. S. L. Pressey's presentation of the teaching machine; B. F. Skinner's teaching machine; Meyer's steps in composing a program for the automated teaching machine; IBM's beginning research on automated courses and the development of the 1500 instructional system; Programmed Logic for Automatic Teaching Operation (PLATO); the 1970s, the era of the microchip, the microcomputer, computer assisted instruction, interactive video programs, computer simulations, and tool software; and the 1980s and 1990s refinement of the software and the development of CD-ROM. The development of two software companies, Sunburst Communications and Tom Snyder Productions, is used to explain the maturation process of simulation software. Several future trends are identified: (1) the use of multimedia will expand rapidly; (2) the use of telecommunications will explode; (3) preservice teacher education programs will change to supply new teachers with the capabilities to make effective use of available technology; (4) the collapse of educational software publishers into fewer companies will continue; and (5) students will benefit from the infusion of technology into the educational process. (Contains 11 references.) (ALF)