This book constitutes the refereed proceedings of the 13th International Conference on String Processing and Information Retrieval, SPIRE 2006, held in Glasgpw, UK in October 2006.

The 26 revised full papers and 5 revised short papers presented together with 2 invited talks were carefully reviewed and selected from 102 submissions. The papers are organized in topical sections on Web clustering and text categorisation, strings, user behaviour, Web search algorithms, compression, correction, information retrieval applications, bio-informatics, and Web search engines.