The annual conference of the European Association for Computer Science Logic (EACSL) CSL 2009
was held in Coimbra (Portugal) September 7-11 2009. The conference series started as a
programme of International Workshops on Computer Science Logic and then at its sixth meeting
became the Annual C- ference of the EACSL. This conference was the 23rd meeting and 18th EACSL
conference it was organized at the Department of Mathematics Faculty of S- ence and
Technology University of Coimbra. In response to the call for papers a total of 122 abstracts
were submitted to CSL 2009of which 89 werefollowedby a full paper. The ProgrammeCommittee
selected 34 papers for presentation at the conference and publication in these proceedings. The
Ackermann Award is the EACSL Outstanding Dissertation Award for Logic in Computer Science. The
awardrecipient for 2009 was Jakob Nordstr¨ om. Citation of the award abstract of the thesis
and a biographical sketch of the recipient may be found at the end of the proceedings. The
award was sponsored for the years 2007-2009 by Logitech S.A.
