The 11th Symposium on Trends in Functional Programming took place on the University of Oklahoma campus in Norman, Oklahoma, May 17-19, 2010. The program included presentations of 26 papers submitted by researchers from six nations and an invited talk by J. Strother Moore on machine reasoning so well received that the question/answer session continued for a full hour beyond the talk, well into the lunch period. Most of the authors submitted revisions of their papers, based in part on responses to their presentations. The revisions were reviewed and discussed in detail by the Program Committee, and 13 of them were accepted for publication in this volume.

A little over half of the revisions accepted for publication were student papers (that is, papers with a student as first author). Following a long-established custom, the Program Committee designated one of them as the best student paper. This year the award went to Stephen Chang for his paper, with co-authors David van Horn and Matthias Felleisen, describing a way to evaluate a call-byneed λ-calculus on the control stack. The Program Committee appreciates the originality and insight in this work and congratulates Stephen Chang on earning the award.

TFP aspires to be a forum for new directions in functional programming research. This year was no exception. Presentations covered new ideas for refactoring, managing source-code complexity, functional language implementation, graphical languages, applications of functional programming in pure mathematics, type theory, multitasking and parallel processing, distributed systems, scientific modeling, domain-specific languages, hardware design, education, and testing.

The editors want to thank the Program Committee and all of the referees for their diligence and for their well-considered reviews. We also want to thank the University of Oklahoma and Erlang Solutions Ltd, for their generous support. Finally, we thank the participants for their lively attention during the symposium. We trust that a good time was had by all.