The book "String Processing and Information Retrieval" is a collection of peer-reviewed contributions from the 16th Symposium on String Processing and Information Retrieval (SPIRE 2009), which took place in August 2009 in Saariselkä, Finland. It includes 34 revised full texts selected from 84 submitted papers. The contributions are organized into thematic sections that address various aspects of string processing, including algorithms for trees, compressed indexes, data compression, content analysis, string algorithms, and their applications in bioinformatics and theoretical foundations. This specialized book is aimed at researchers and practitioners in the field of computer science and provides valuable insights into current developments and techniques in string processing and information retrieval.