The Lisp family of languages has traditionally been a privileged domain where linguistic experiments were done, this paper presents a new dialect offering concurrency and distribution. This dialect, nicknamed CD-Scheme, has been designed above Scheme with as few as possible features to allow a great expressiveness but still to retain the original consistency and simplicity of Scheme. We explicitly show how common parallel constructs can be written in regular CD-Scheme. A denotational semantics is also presented that expresses the detailed meaning of assignment, data mutation, continuations in presence of concurrency and distribution. This semantics offers a basis to understand new proposals of concurrent or distributed features and may be used to justify compiler optimizations or implementation techniques. The proposed set of features of CD-Scheme can be also used to extend languages other than Scheme. CD-Scheme is a concurrent, distributed and conservative extension of Scheme, a dial...