Communication is becoming one of the central elements in software development. As a potential typed foundation
for structured communication-centred programming, session types have been studied over the last
decade for a wide range of process calculi and programming languages, focussing on binary (two-party)
sessions. This work extends the foregoing theories of binary session types to multiparty, asynchronous sessions,
which often arise in practical communication-centred applications. Presented as a typed calculus for
mobile processes, the theory introduces a new notion of types in which interactions involving multiple peers
are directly abstracted as a global scenario. Global types retain the friendly type syntax of binary session
types while specifying dependencies and capturing complex causal chains of multiparty asynchronous interactions.
A global type plays the role of a shared agreement among communication peers, and is used as a
basis of efficient type checking through its projection onto individual peers. The fundamental properties of
the session type discipline such as communication safety, progress and session fidelity are established for
general n-party asynchronous interactions.