The annual conference of the European Association for Computer Science Logic (EACSL), CSL 2012, was held in Fontainebleau, France, from 3 to 6 September 2012. CSL started as a series of international workshops on Computer Science Logic, and became at its sixth meeting the Annual Conference of the EACSL. This conference was the 26th workshop and 21th EACSL conference; it was organized by the Department of Computer Science of the Institut Universitaire de Technologie, IUT de Sénart Fontainebleau, of the university Paris Est Créteil (UPEC).

For the conference, a total of 35 papers were selected for presentation together with 3 invited talks. Proceedings were published as volume 16 of the Dagstuhl LIPICS series. For this special issues, several papers were chosen by the guest editors and their authors were invited to submit an extended version of their work. Each submitted article has then been peer-reviewed by at least two experts of the field. This process results in a total of 7 papers that represents the wideness and the richness of the usual topics of CSL from automata theory, proof theory, semantics of programming language to decidability results, definability issues and finite models.

We are sincerely grateful to all members of the Programme Committee, the reviewers, and to all authors who have submitted their work to CSL.