Mobile Computation with Functions explores distributed computation with languages which adopt functions as the main programming abstraction and support code mobility through the mobility of functions between remote sites. It aims to highlight the benefits of using languages of this family in dealing with the challenges of mobile computation. The possibility of exploiting existing static analysis techniques suggests that having functions at the core of mobile code language is a particularly apt choice. A range of problems which have impact on the safety, security and performance are discussed. It is shown that types extended with effects and other annotations can capture a significant amount of information about the dynamic behavior of mobile functions, and offer solutions to the problems under investigation. This book includes a survey of the languages Concurrent ML, Facile and PLAN which inherit the strengths of the functional paradigm in the context of concurrent and distributed computation. The languages which are defined in the subsequent chapters have their roots in these languages.