Hal Abelson’s, Jerry Sussman’s and Julie Sussman’s Structure and Interpretation of Computer Programs (MIT Press, 1984; ISBN 0-262-01077-1) is an excellent computer science text used in introductory courses at MIT.
The book’s homepage is at: http://mitpress.mit.edu/sicp/.
The full text of the book is available online.
The book is dedicated ”in respect and admiration, to the spirit that lives in the computer”.
Also known as The Wizard Book.