Grammatical evolution tutorial

These proceedings contain the papers presented at the 12th Annual Genetic and Evolutionary Computation Conference (GECCO-2010), held in Portland, USA, July 7-11, 2010. This year, we received 373 submissions, of which 168 were accepted as full eight-page publication with 25 minute presentation during the conference. This corresponds to an acceptance rate of 45%. In addition, 110 submissions (29%) have been accepted for poster presentation with two-page abstracts in the proceedings. GECCO works according to the motto one conference, many mini-conferences. This year, there were 15 separate tracks that operated independently from each other. Each track had its own track chair(s) and individual program committee. To ensure an unbiased reviewing process, all reviews were conducted double blind; no authors' names were revealed to the reviewers. About 560 researchers participated in the reviewing process. We want to thank them for all their work, which is highly appreciated and absolutely vital to ensure the high quality of the conference. In addition to the presentation of the papers contained in these proceedings, GECCO-2010 also included free tutorials, workshops, a series of sessions on Evolutionary Computation in Practice, various competitions, and late-breaking papers.