This volume, like the symposium CSP25 which gave rise to it, commemorates the semi-jubilee of Communicating Sequential Processes. 1 Tony Hoare s paper Communicating Sequential Processes is today widely regarded as one of the most in?uential papers in computer science. To comm- orate it, an event was organized under the auspices of BCS-FACS (the British Computer Society s Formal Aspects of Computing Science specialist group). CSP25 was one of a series of such events organized to highlight the use of formal methods, emphasize their relevance to modern computing and promote their wider...