We would like to thank the many people who have helped us develop this book and this curriculum.

Our subject is a clear intellectual descendant of “6.231,” a wonderful subject on programming linguistics and the lambda calculus taught at MIT in the late 1960s by Jack Wozencraft and Arthur Evans, Jr.

“A computer is like a violin. You can imagine a novice trying first a phonograph and then a violin. The latter, he says, sounds terrible. That is the argument we have heard from our humanists and most of our computer scientists. Computer programs are good, they say, for particular purposes, but they aren’t flexible. Neither is a violin, or a typewriter, until you learn how to use it.”

Marvin Minsky, “Why Programming Is a Good Medium for Expressing Poorly-Understood and Sloppily-Formulated Ideas”

“Is it possible that software is not like anything else, that it is meant to be discarded: that the whole point is to always see it as a soap bubble?”

Alan J. Perlis

Educators, generals, dieticians, psychologists, and parents program. Armies, students, and some societies are programmed. An assault on large problems employs a succession of programs, most of which spring into existence en route. These programs are rife with issues that appear to be particular to the problem at hand. To appreciate programming as an intellectual activity in its own right you must turn to computer programming; you must read and write computer programs — many of them. It doesn’t matter much what the programs are about or what applications they serve.

This book is dedicated, in respect and admiration, to the spirit that lives in the computer.

“I think that it’s extraordinarily important that we in computer science keep fun in computing. When it started out, it was an awful lot of fun. Of course, the paying customers got shafted every now and then, and after a while we began to take their complaints seriously. We began to feel as if we really were responsible for the successful, error-free perfect use of these machines. I don’t think we are.

This book is one of a series of texts written by faculty of the Electrical Engineering and Computer Science Department at the Massachusetts Institute of Technology. It was edited and produced by The MIT Press under a joint production-distribution arrangement with the McGraw-Hill Book Company.

Structure and Interpretation
of Computer Programs