In the introduction to this book, the authors have included a section entitled 'What this Book is Not About'. This section explains that it is not for the inexperienced user, nor is it intended to replace the Acorn Programmer's Reference Manual (PRM).

Instead it is intended to make complex information easier to understand.

After brief introductions to Risc technology, ARM instructions, the Basic Assembler and the OS itself, the book concentrates on the most useful aspects of the Operating System for experienced programmers. This includes filing systems, window and font managers, character input/output, interrupts and vectors. There is a comprehensive description of the sound facilities, and some particularly helpful information on writing modules and applications.

All the useful SWI (software interrupt) calls are described clearly and logically, and there are plenty of program listings which illustrate the use of many of the calls. Some of these are useful programs in their own right, for example, a printer buffer, and a supplementary program disc is available which contains them all, together with several extra utilities.

Both authors have worked for Acorn and clearly know their topic well. However, despite the complexity of much of the material, the book is written with a clarity often lacking in such works. For the experienced programmer who wants to explore the exciting facilities of the Archimedes, this book is excellent.

Its scope is neatly summed up: it is a highly readable, in-depth guide to the complexities of the Archimedes Operating System, applicable to both Arthur and Risc OS.

However, there are some aspects which are not covered at all, for example, sprites. I suspect that even if you have the PRM on your shelf, you will always turn to this book first.