The words were well deserved and DK achieved sales of over Pounds 4 million in six months. Now, with the success to match the superlatives in their titles, editions in French, Spanish and German are in production and five brand new ones are about to be launched.

Eyewitness Encyclopaedia of History and the Eyewitness Encyclopaedia of Nature follow on from the Eyewitness Encyclopaedia of Science in that first wave.

The history title screen has a console where you choose one of 10 time zones. And as the lights literally rise on, say, 1900-1945, you see a gas mask, a saxophone and pictures of Lenin, the Blitz and Hiroshima.

You can click on a place on a globe to find a topical event or explore those artefacts. For example, you’ll hear a speech by Lenin or see film of the “subway” shelters during the Blitz. While video sequences like this were better quality than usual, the audio and some of the content are worryingly American.

In Nature the console idea appears again, this time it leads to 10 habitats instead of time zones. Choose one like “woodlands” and you see the habitat where you can click on a bird, or read about the climate or see a food “web”.

Set beside the vague and largely cosmetic Science title, this rough copy hints of something more coherent. Set beside the publisher’s books of the same name you soon see what is special: you can explore the information from several angles.

As there is no way this massive subject fits on one disc, I still can’t see this vital cross-referencing being as thorough as it is in, say, The Way Things Work. It’s pure coincidence I guess, but that disc alone has been the most successful so far, selling 50,000 out of 170,000 spread over five titles.

At its best, this CD-Rom technology is like a library where you needn’t leave your seat and where links between things are easily made. But actually, what is wanted is something less passive. Instead, children might take the words and pictures they find to use in project work. The new discs still don’t let you copy the text and edit it - they don’t let you re-write, for example, even a second of history.

Still, these are the benchmark CD-Rom “fact books”. Dorling Kindersley has not just put information on to CD-Rom - it has made it really easy and enjoyable to get the information off again. Why that should be special is a complete mystery. The publisher’s 120-strong multimedia team is a big cannon, but that doesn’t buy a monopoly on imagination.

Coming next is the World Reference Atlas which promises statistics on climate, resources, trade and dynamic maps. At the other end of the market, and obviously of no interest to TES readers, is Anne Hooper’s Ultimate Sex Disc.

* Dorling Kindersley

Titles are available through computer outlets and mail order. Prices range from Pounds 39 to Pounds 69. These versions are for PC Windows; Macintosh versions should appear in the autumn.