This book constitutes the thoroughly refereed post-workshop proceedings of the 9th International Workshop on Implementation of Functional Languages, IFL'97, held in St. Andrews, Scotland, UK, in September 1997.The 21 revised full papers presented were selected from the 34 papers accepted for presentation at the workshop during a second round of thorough a-posteriori reviewing. The book is divided in sections on compilation, types, benchmarking and profiling, parallelism, interaction, language design, and garbage collection.