This special issue contains revised and extended versions of papers presented at the 26th Annual IEEE Symposium on Logic in Computer Science (LICS 2011), held at the Fields Institute in Toronto, Canada in June 2011. The six articles that were invited to this special issue span a wide range of topics represented at LICS: bounded arithmetic, type theory, semantics, domain theory, automata theory, and game theory. The articles were selected from the 32 papers presented at the conference.

We thank all authors of this special issue for their contributions. All papers were refereed to the usual high standards of LMCS. We thank the referees of these papers as well as the program committee members and their subreviewers who reviewed the original conference submissions for their excellent work.