This tutorial book presents seven carefully revised lectures given at the 6th International School on Functional Programming, AFP 2008, in Heijen, The Netherlands in May 2008.The book presents the following seven, carefully cross-reviewed chapters, written by leading authorities in the field: Self-adjusting: Computation with Delta ML, spider spinning for dummies, from reduction-based to reduction-free normalization, libraries for generic programming in Haskell, dependently typed programming in agda, parallel and concurrent programming in Haskell and an iTask case study: a conference management system.