This Festschrift has been published in honor of Rinus Plasmeijer, to celebrate the combined occasion of his 61st birthday and the 25th Symposium on Implementation and Application of Functional Languages, IFL 2013, held in Nijmegen, The Netherlands, in August 2013. Rinus Plasmeijer was the main designer of the lazy functional programming language "Clean" and has always been the leader of the associated research team. He has played a decisive role in making the Radboud University of Nijmegen an important center of research in functional programming by organizing and hosting the first few IFL symposia in Nijmegen. This Festschrift contains 19 scientific essays written by former PhD students of Rinus Plasmeijer and researchers in the field of functional programming who have collaborated with him. The authors write about the influence the beauty of functional programming has had or still has on their work.

This volume contains the revised lecture notes corresponding to the lectures given at the 6th International School on Advanced Functional Programming, AFP 2008, held in Heijen, a little village in the woodlands near the city of Nijmegen, The Netherlands, May 19-24, 2008. AFP 2008 was co-located with TFP 2008, the 9th Symposium on Trends in Functional Programming [see P. Achten,P.Koopman,M.Marazan ' : Trends in Functional Programming volume 9, ISBN 978-1-84150-277-9,Intellect]. The school attracted 62 participants from 19 countries, a record, including the lecturers and organizers. This event was precededby?veearlierinstancesinB? astad,Sweden(1995,LNCS925),Olympia, WA, USA (1996, LNCS 1129), Braga,Portugal(1998, LNCS 1608), Oxford, UK (2002, LNCS 2638) and Tartu, Estonia, (2004, LNCS 3622). The goals of the series of Advanced Functional Programming schools are: - Bringing computer scientists, in particular young researchers and progr- mers, up to date with the latest functional programming techniques. - Showinghowtouseadvancedfunctionalprogrammingtechniquesin"progr- ming in the real world". - Bridgingtheeducationalgapbetweenresultspresentedatconferencesonthe one side and material as presented in introductory textbooks on the other side.

This book constitutes the thoroughly refereed post-proceedings of the 12th International Workshop on Implementing Functional Languages, IFL 2000, held in Aachen, Germany in September 2000.The 15 revised full papers presented have gone through a thorough round of post-workshop reviewing and were selected from 33 workshop presentations. Among the topics covered are language concepts, type checking, compilation techniques, abstract interpretation, automatic program generation, abstract machine architectures, array processing, concurrent and parallel processing, heap management, runtime profiling, performance measurement, debugging and tracing, and tools and programming techniques.

This book constitutes the thoroughly refereed post-workshop proceedings of the 11th International Workshop on the Implementation of Functional Languages, IFL'99, held in Lochem, The Netherlands, in September 1999.
The 11 revised full papers presented were carefully selected during two rounds of reviewing. The papers are organized in sections on applications, compilation techniques, language concepts, and parallelism.