Communicating Sequential Processes (CSP)

Communicating Sequential Processes, or CSP, is a language for describing patterns of interaction. It is supported by an elegant, mathematical theory, a set of proof tools, and an extensive literature. The book Communicating Sequential Processes was first published in 1985 by Prentice Hall International (who have kindly released the copyright); it is an excellent introduction to the language, and also to the mathematical theory.

An electronic version of the book has been produced, and may be copied, printed, and distributed free of charge. However, such copying, printing, or distribution may not: be carried out for commercial gain; or - for copyright reasons - take place within India, Pakistan, Bangladesh, Sri Lanka, or the Maldives; or involve any modification to the document itself.

To obtain the electronic version, click here; it is available only in Adobe PDF, version 1.4, and can be viewed, and printed, using the free version of Acrobat Reader. Questions and comments are welcome, and should be sent to the editor. We will be updating this site periodically, and any changes or additions will be announced via email; to join the mailing list, send a message to

The author, Tony Hoare, was Professor of Computation at Oxford, and is now a senior researcher at Microsoft Research. The editor of this version, Jim Davies, is the Director of the Software Engineering Centre at Oxford; the Centre offers short courses in CSP and its applications, as part of a programme of advanced, professional education in software engineering.