This is a comprehensive account of the semantics and implementation of the whole Lisp family of languages, namely Lisp, Scheme and related dialects. It describes 11 interpreters and 2 compilers, including very recent techniques of interpretation and compilation. The second part focuses more on implementation techniques and discusses precompilation for fast interpretation: threaded code or bytecode; compilation to C. This will be the new standard reference for people who want to know more about the Lisp family of languages: how they work, how they are implemented, what their variants and why such variants exist.