Encyclopedists, close cousins to dictionary-makers, are a gentle, somewhat grey breed, who have suddenly found themselves part of what is possibly the fastest growing industrial sector in the world - that of electronic communication.

Encyclopedias on CD-Rom are proliferating in a way that few publishers could have foreseen, even a decade ago.

Until now, most have been created with the American user in mind, although their developers are beginning to clothe both text and multimedia in native costume.

Each new edition offers ever “more” and “better” features; for example, access to updated information and services on the Internet, direct dialogue with the publishers via e-mail (electronic mail), or a whole library of reference works piled high on to the same disc.

Competition is fierce and prices continue to tumble, but sales hype should rarely be believed. All encyclopedias are highly selective in their content. Even in the most distinguished publishing houses, information may be included because of an editor’s own cultural background or excluded by default.

Even bare numerical statistics (such as the number of words, entries or videos) can be misleading. For example, although encyclopedias such as Microsoft’s Encarta boast an impressive number of entries, they may skimp on biographical and geographical entries.

They may also be short on the kind of stimulating coverage that offers several sides to, say, the Vietnam War or environmental issues. Again, it is not the number of videos and animations that should impress, but whether by their content and length these genuinely add to our understanding of the subject.

Publishers, however august, are pushing their wares to a dizzying range of buyers. Most have now recognised the hunger, almost of famine proportions, for electronic information.

Even the major players are sequestering the rights to encyclopedias that died natural deaths decades ago. Fed back into the editorial word-mill, their contents swell the size of existing volumes.

In between lies a brisk market in encyclopedias whose text is licensed out to publishers in different parts of the world, to be sold under different titles and at widely differing prices.

A member of the public who buys, for example, the US edition of Softkey’s Infopedia at the give-away price of $49.95 (about Pounds 34), is acquiring largely the same text (with multimedia elements added) as that found in Funk Wagnall’s Encyclopedia, sold at check-outs in US supermarkets: the very same product on which Microsoft’s technologically glittering Encarta is based.

The UK edition of Infopedia (a disc containing a library-shelf of reference books, recently launched at Pounds 39.99), throws in the Hutchinson Multimedia Encyclopedia, licensed to Softkey by Helicon. What is more, the very same (or a slightly abridged and earlier version) of Hutchinson’s is sold in Softkey’s “platinum range” under the name of Webster’s Concise Interactive Encyclopedia - at the knock-down price of Pounds 12.

However, anyone buying the Hutchinson Multimedia Encyclopedia disc will find that this includes an atlas, a dictionary, an “On this Day” feature, a quiz containing questions from the national curriculum, several thousand quotations, 500 bibliographies, and a popular e-mail service enabling users in any part of the globe to contact the Oxford-based publisher.

Softkey’s UK edition of Infopedia offers a multimedia library shelf that contains the 1985 edition of the Concise Dictionary of National Biography published by Oxford University Press, together with the ubiquitous Hutchinson Multimedia Encyclopedia, the Bloomsbury Dictionary of Quotations and five further British reference works. Because the text in these items has not been co-ordinated, some quite serious factual discrepancies occur.

Bridget Martyn is a freelance encyclopedist who has been involved in the Oxford Children’s Encyclopedia, Hutchinson Multimedia Encyclopedia and Encarta, and has worked for the publisher of World Book.