Human Problem Solving (1972) by Allen Newell and Herbert Simon of Carnegie-Mellon University, a tome of over 900 pages, was the summa of some 17 years of research by Newell, Simon, and their numerous associates (most notably Cliff Shaw, a highly gifted programmer at Rand Corporation) into “how humans think.” “How humans think” of course belonged historically to the psychologists’ turf. But what Newell and Simon meant by their project of “understanding . . . how humans think” was very different from how psychologists envisioned the problem before these two men invaded their milieu in 1958 with a paper on human problem solving in the prestigious Psychological Review. Indeed, professional psychologists must have looked at them askance. Neither was formally trained in psychology. Newell was originally trained as a mathematician, Simon as a political scientist. They both disdained disciplinary boundaries. Their curricula vitae proclaimed loudly their intellectual heterodoxy. At the time Human Problem Solving was published, Newell’s research interests straddled artificial intelligence, computer architecture, and (as we will see) what came to be called cognitive science. Simon’s multidisciplinary creativity—his reputation as a “Renaissance man”—encompassing administrative theory, economics, sociology, cognitive psychology, computer science, and the philosophy of science—was of near-mythical status by the early 1970s. Yet, for one prominent historian of psychology it would seem that what Newell and Simon did had nothing to do with the discipline: the third edition of Georgetown University psychologist Daniel N. Robinson’s An Intellectual History of Psychology (1995) makes no mention of Newell or Simon. Perhaps this was because, as Newell and Simon explained, their study of thinking adopted a pointedly information processing perspective. Information processing: Thus entered the computer into this conversation. But, Newell and Simon hastened to clarify, they were not suggesting a metaphor of humans as computers. Rather, they would propose an information processing system (IPS) that would serve to describe and explain how humans “process task-oriented symbolic information.” In other words, human problem solving, in their view, is an instance of representing information as symbols and processing them.