Structure and Interpretation of Computer Programs

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.

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Second edition All rights reserved. No part of this book may be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, or information storage and retrieval) without permission in writing from the publisher. This book was set by the authors using the L^ATEX typesetting system and was printed and bound in the United States of America.

Library of Congress Cataloging-in-Publication Data


Abelson, Harold
    Structure and interpretation of computer programs / Harold Abelson
 and Gerald Jay Sussman, with Julie Sussman.--2nd ed.
    p. cm.--(Electrical engineering and computer science
 series)
    Includes bibliographical references and index.
    ISBN 0-262-01153-0 (MIT Press hardcover)
    ISBN 0-262-51087-1 (MIT paperback)
    ISBN 0-07-000484-6 (McGraw-Hill hardcover)
    1. Electronic digital computers--Programming. 2. LISP (Computer
 program language) I. Sussman, Gerald Jay.  II. Sussman, Julie.
 III. Title.  IV. Series: MIT electrical engineering and computer
 science series.
 QA76.6.A255     1996                                  96-17756
 005.13'3--dc20

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. I think we're responsible for stretching them, setting them off in new directions, and keeping fun in the house. I hope the field of computer science never loses its sense of fun. Above all, I hope we don't become missionaries. Don't feel as if you're Bible salesmen. The world has too many of those already. What you know about computing other people will learn. Don't feel as if the key to successful computing is only in your hands. What's in your hands, I think and hope, is intelligence: the ability to see the machine as more than when you were first led up to it, that you can make it more.''

Structure and Interpretation of Computer Programs

second edition

Structure and Interpretation
of Computer Programs