The Acorn Electron opens up an infinitely wide world of applications programming to users at home, in schools and in small businesses. Acorn BASIC is particularly powerful and sophisticated and the fact that the Electron has a built-in assembler allows the user to gain extra speed and flexibility by incorporating assembly language routines in BASIC programs with surprising ease. This book is aimed at Electron users who have already gained some experience with BASIC and is intended to extend programming skills to a high level of proficiency. The book will be an invaluable source of reference for Electron programmers who want to use the full potential of Acorn BASIC combined with the assembly language facilities the Electron offers. The introductory chapters discuss principles of good programming practice. Separate chapters are then devoted to data processing and file handling. Other chapters discuss how to achieve the finishing touches that distinguish 'user-friendly' programs, how to go about designing large programs and how to find the bugs concealed in machine code. Ways of using the MOS are discussed and a variety of invaluable utilities - including a trace debugger, a spelling checker and a disassembler - are presented to enable users to go even further in developing their own software. The final chapter deals with Boolean logic and bit manipulation. *The Authors* Mike James and S. M. Gee have written several other very successful books on programming. They are both regular contributors to the monthly computing magazines. *Front cover illustration by Alan Craddock*