Free Prolog Books
An introduction to logic programming through Prolog
Originally published in 1996, this now out of print book gives a simple introduction to the theory of logic programming, and also describes in detail an implementation of a small Prolog dialect called picoProlog by an interpreter written in Pascal. The full text of the book is availabe in pdf format as is the Pascal source code for the interpreter.
Natural Language Processing Techniques in Prolog
This is material for a course about using computers to process language. Since it is assumed that the reader has no previous experience in programming, great care is taken to provide a simple yet comprehensive introduction to Prolog.
Natural Language Processing for Prolog Programmers (pdf link)
Designed to bridge the gap for those who know Prolog but have little or no background in linguistics, this book concentrates on turning theories into practical techniques. This is another out of print work now available for free in digital form.
Prolog Programming in Depth (pdf link)
This is a free digital version of a Prolog book that was published in 1997 and is out of print.
Learn Prolog Now!
This is the first draft of a book about Prolog. It is based on the experience of teaching Prolog at the Department of Computational Linguistics, University of the Saarland.
Building Expert Systems in Prolog
Online Prolog book.
Adventure in Prolog
Online Prolog book.
Prolog Programming A First Course
This site has course notes "intended for undergraduate students who have some programming experience and may even have written a few programs in Prolog." The notes can be downloaded in book form as a postscript file or read online and include samples and exercises.
Logic, Programming and Prolog (2ed
Free Prolog book in pdf form. You no longer have to enter your name and an e-mail address to download the book.
Artificial Intelligence through Prolog by Neil C. Rowe
Free online Prolog book in html form.