One of the challenges in working with heterogeneous Web services is the need to ensure their interoperability and compatibility. In the context of Web service interaction, significant research efforts focusing on the adaptation techniques have been made to tackle the services incompatibilities. This chapter presents an overview of proposed adaptation approaches dealing with service mismatches at the level of service functional specifications, i.e. service interface and business protocol. It focuses on the behavior and interface of Web services interacting with an environment. The Web service composition and the crucial concepts of Web services are discussed in detail. The chapter argues the incompatibility of service interaction at interface and protocol levels. Finally the chapter focuses on how framework, Processes with Adaptive Web Services (PAWS) selects and adapts candidate services for a composed process.