SWI-Prolog reference manual
Google's Protocol Buffers Library SWI-Prolog SSL Interface SWI-Prolog HTTP support Paxos -- a SWI-Prolog replicating key-value store SWI-Prolog Semantic Web Library 3.0 SWI-Prolog Source Documentation Version 2 SWI-Prolog Regular Expression library SWI-Prolog YAML library Managing external tables for SWI-Prolog SWI-Prolog ODBC Interface A C++ interface to SWI-Prolog SWI-Prolog RDF parser SWI-Prolog binding to BSD libedit SWI-Prolog C-library Redis -- a SWI-Prolog client for redis SWI-Prolog Natural Language Processing Primitives SWI-Prolog binding to GNU readline SWI-Prolog binding to zlib SWI-Prolog binding to libarchive Transparent Inter-Process Communications (TIPC) libraries Constraint Query Language A high level interface to SQL databases Pengines: Web Logic Programming Made Easy SWI-Prolog SGML/XML parser Prolog Unit Tests SWI-Prolog Unicode library
A paperback version of the manual is available.