Method Engineering has emerged in response to the need to adapt methods to better fit the needs of the development task at hand. It aims at providing techniques for retrieving reusable method components, adapting and assembling these together to form the new method. The paper provides a survey of the main results obtained for the two issues of defining and assembling components. Given the amplitude of the results obtained, the paper concludes that the research community has reached considerable maturity. It argues thereafter that the full power of method components can be widely exploited by moving to the notion of method services and briefly outlines a possible approach towards MaaS, Method as a Service.