AbstractWe give a compositional denotational semantics for a real-time distributed language, based on the linear history semantics for CSP of Francez et al. Concurrent execution is not modelled by interleaving but by an extension of the maximal parallelism model of Salwicki and Müldner, that allows for the modelling of transmission time for communications. The importance of constructing a semantics (and, in general, a proof theory) for real-time is stressed by such different sources as the problem of formalizing the real-time aspects of Ada and the elimination of errors in the real-time flight control software of the NASA space shuttle (Comm. ACM 27 (1984))