How did it all begin? Nobody knows. The start of the story is lost in the mists of antiquity, and the sands of time have drifted over the opening chapter. One minute there was talk of how micros would bring user-friendliness to manking, and the next minute there was CP/M.

Saddled with CP/M, we've been trying to make the best of it ever since. This book tacitly recognises this noble struggle fairly early on: "When you buy CP/M you usually receive copies of the official CP/M manuals... It's safe to say that beginners have found these manuals confusing. Several less charitable adjectives have also been used."

So, in order to give CP/M the benefit of the doubt, you need to approach it through a third party, in this case Dwyer and Critchfield. And let's admin straight away, you could do a lot worse.

This is perhaps as lucid and useful a book on CP/M (and related products) as you could hope to find. It covers a remarkable amount of ground at an even pae with a sprinkling of whimsical illustrations (plus colour) and text that is made to look interesting and that reads well.

It isn't cheap, but if you sat down and worked your way through almost 500 pages you'd probably cover something equivalent to a degree course. And it won't just be CP/M you'll have graduated in, but also a wide variety of programming concepts and a fair range of program products. Among the latter is Unix, which may be the subject of the next such book you'll need to look at if the irresistible march of fashion proceeds unchecked.