This book presents a set of 8 papers accompanying the lectures of leading researchers given at the 9th edition of the International School on Formal Methods for the Design of Computer, Communication and Software Systems, SFM 2009, held in Bertinoro, Italy, in June 2009. SFM 2009 was devoted to formal methods for web services and covered several aspects including coreography, orchestration, description techniques, interaction, synthesis, composition, session types, contracts, verification, security, and performance.