This book arrived for review just as I was trying to persuade a Dragon owner to learn machine code. It made a good first impression and, having read it thoroughly, I can make two recommendations:

Firstly, anyone wishing for a meaty, well-paced, interesting guide to the 6809 should buy this book. Secondly, the Guinness Book of Records should consider it for the book with the most mistakes! I gave up counting but there's at least one misprint on every page and there are more than 200 pages.

How is it possible to recommend a book with such a disgraceful standard of proof-reading, especially when a large part of the book is devoted to a Basic program to assembler the machine code?

The answer is that, all the same, it has a lot going for it: it is well conceived and persuasively written by someone who appears to have a clear grasp of what the 6809 can and should do - and, above all, appreciates what newcomes can and should learn.

The instructions are covered in logical groups, chapter by chapter. The Basic assembler is put in similarly, but is kept separate and there is no confusion. We didn't spot errors in the actual code, and the program is clearly written and well explained.

There is a micro project at the end of most chapters - limited, but with answers - and a chapter on writing a ping-pong game, recognising most people will want to learn assembler to use fast-moving graphics.

Points specific to the Dragon (sound, interrupts, ROM calls) get a good mention and I felt confident Mike James actually uses a Dragon himself.

The style is easy and suitable for any level. Highly recommended, but I hope both author and publisher give themselves a big rap over the knuckles.

Kenn Garroch