*About this book* This book described the Acornsoft LISP system for the BBC Microcomputer and Acorn Electron. It provides a complete introduction to LISP and assumes no previous knowledge of the language. LISP is the fundamental language of artificial intelligence research and provides more flexibility in data and control structures than traditional languages. LISP is easy to learn and is widely used for writing substantial and sophisticated programs with practical applications including design of education systems and medical research. The Acornsoft LISP system features a number of functions not found in other LISP systems such as the VDU function which provides an easy interface to the BBC Microcomputer Machine Operating System. Use of this additional function is completely explained in this book and illustrated with many example programs. The second half of this book is devoted to many example programs. These include a tree-sorting program, an arbitrary arithmetic package, an animal guessing game, a route finding program, a graphics package, a simple compiler and an adventure game. *About the authors* Dr. Arthur Norman is a lecturer in computer science at the University of Cambridge, specialising in research into LISP and other list processing languages and their application to algebraic manipulation. He has worked closely with Acornsoft on a number of occasions including advising on the Acornsoft implementation of LISP. Gillian Cattell did research into the LISP language at Cambridge University and is now working at the National Physical Laboratory at Teddington.