This volume is published in Honor of Philip Wadler on the occasion of his 60th birthday, and the collection of papers form a Festschrift for him. The contributions are made by some of the many who know Phil and have been influenced by him. The research papers included here represent some of the areas in which Phil has been active, and the editors thank their colleagues for agreeing to contribute to this Festschrift. We attempt to summarize Phil Wadler's scientific achievements. In addition, we describe the personal style and enthusiasm that Phil has brought to the subject.