Distributed systems are fast becoming the norm in computer science. Formal mathematical models and theories of distributed behavior are needed in order to understand them. This book proposes a distributed pi-calculus called Dpi, for describing the behavior of mobile agents in a distributed world. It is based on an existing formal language, the pi-calculus, to which it adds a network layer and a primitive migration construct. A mathematical theory of the behavior of these distributed systems is developed, in which the presence of types plays a major role. It is also shown how in principle this...