This clear and comprehensive introduction to compilers and interpreters emphasises the practical side of the art. It moves gradually from the idea of a 'wedge' in the BBC computer's Operating System, to a simple interpreter, a simple graphics language, threaded interpretive languages (including FORTH) and, finally, a stand-alone compiler. Listings of the implementations are given. This book will give anyone with a good knowledge of assembly language the foundation on which to build an interpreter or compiler of their own. Bruce Smith has written sixteen books on computing, fourteen of which have dealt with the BBC Computer range. He is currently technical editor of Acorn User magazine.