IT IS GOOD to see such a rabid interest in the Psion business packages but, with the dearth of books on other QL subjects, it's about time a halt was called to the production line.

The latest off the conveyor belt is Word Processing with QL Quill, by David Dempsey. His book is a practical tutorial with exercises at the end of each section, and information accompanied by diagrams.

Unfortunately, the book is a bit of a slow starter. The first two chapters describe the functions of a word processor and show how Quill is loaded into the QL.

By page 52 we have learnt how to make back-up copies and Dempsey has explained the characteristics of QL cartridges.

That page is the turning point of the book, which goes on to describe formatting techniques and advanced editing features such as the import command.

The Sinclair Quill manual gives few examples of how to set up a document with margin settings, underlining, and various typefaces. It also gives a garbled account of how to set tabulation points on a page. That is one of the most difficult aspects to understand, and Dempsey gives a simple and readable explanation.

The section on advanced editing covers such topics as placing headers on the page, and importing text from a file produced by one of the other Psion packages. It is a lucid and well designed account of those processes.

The final chapter of the book looks at printing, a topic which is largely ignored in the manual.

Although he says little about the types of printer you can use with Quill - a glaring omission - Dempsey does provide a survey of the types of printing you can do.

The only other book which can be compared in terms of quality with Dempsey's is QL Quill, from Century. There is little between them.

Word Processing with QL Quill is for both the business and home user who wants to know more about the machine as well as the package. The combination works well, and if you are interested in the esoteric aspects of QL usage, then the Longman book is a perfect buy.

IT SHOULD BE the answer to all Spectrum programmers' dreams, but The Programmers' Trouble Shooting Guide, by Piers Letcher, is no more than a witch's brew of hackneyed programming ideas and solutions presented in a new format. It is for those people who are not merely beginners, but who have not even bought their computers.

The introduction to the book contains a table listing the types of problems you may encounter with your computer, together with the chapters which cover those instances. For example, if you are unable to run a program, it may be because of typing errors, corrupted memory or locked-in machine code. The answers to those weighty posers are found in chapters two, nine and eleven. They could just as easily be found in the chapters on editing, and memory configuration in the Spectrum manual.

The list will probably get you thinking that at last you have everything you need to know in one book but, unless you are an absolute beginner you will have probably come across such information before.

The first six chapters do little to expand on the information given in the Spectrum manual, but the sections on animation, sound and memory are of some use if you have not bought any other books already on the market. There is also a chapter on machine code and appendices, most of which look as if they have been taken from the Spectrum manual.

Letcher's book suffers from a disease found in many compendiums. He has only been able to scratch the surface of topics which require books and not chapters to explain adequately. You would, therefore, be better off looking elsewhere for an in-depth treatment of graphics and machine code programming. If, however, you are a beginner the book may provide an easy launch pad to better computing.

IF YOU ARE still enamoured with the Spectrum Z-80 processor you may have noticed the lack of good reference material about the instruction set.

There are few books which catalogue the instruction set, show the timings of each command, with examples of usage. The Z-80 Reference Guide comes as a pleasant surprise.

It starts with an introduction to the register sets and a general explanation of timings for each type of instruction. A page is devoted to each instruction giving a general description of usage, the number of bytes used by each, the flags affected by execution.

The book bears a striking resemblance to The Z-80 Programmers' Reference Guide, by Rodney Zaks. That includes a comprehensive course on Z-80 programming, something which Tully's book omits apart from a puny chapter giving hints and tips.

Tully's book will never beat Zaks'. It is, however, useful for beginners who want a quick reference to a particular instruction.