This is the second of two papers in which we present the -calculus, a calculus of mobile processes. We provide a detailed presentation of some of the theory of the calculus developed to date, and in particular we establish most of the results stated in the companion paper. 4 Introduction This is the second of two papers in which we present the -calculus, a calculus of mobile processes. The companion paper [2] contains an introduction to the calculus through a sequence of examples, together...