Wikipedia: Prolog

Learn Prolog Now A free online course (also printed book available).

Prolog Programming A very nice, concise on-line guide to Prolog by Roman Barták. Numerous program examples. Highly recommended.

Adventure in Prolog An introductory on-line book by Dennis Merritt. A nice, good work.

Expert Systems in Prolog Another book on Prolog and Expert Systems by Dennis Merritt.

Prolog Tutorial A nice Prolog tutorial by J.R. Fisher. Numerous examples.

Free Online Prolog Tutorials, Logic Programming Tutorials A site with links to on-line Prolog courses.

Logic Programming and Prolog. A very good, classic book on logical foundations of Prolog and ideas of logic programming with numerous examples is the one by Ulf Nilsson and Jan Małuszyński. You can download the .pdf file. Highly recommended.

Prolog Programming in Depth Another, more practical book. Numerous example solutions and lines of Prolog code.

W.F. Clocksin, C.S. Mellish: Prolog. Programowanie. Helion, Gliwice, 2003.

A. Niederliński: Programowanie w logice z ograniczeniami. Łagodne wprowadzenie dla platformy ECLiPSe. PKJS, Gliwice 2010, 308 + XVIII stron. Strona ksiązki: Programowanie w logice z ograniczeniami

Prolog Lab