The World Book Multimedia Encyclopedia 1995 edition. Mac and Windows versions, pounds 99, (01734 773423); Microsoft Encarta 1995, pounds 49.99.

Encyclopaedias have been at the forefront of the multimedia revolution. That is not surprising: a CD-Rom can pack in not only the full text but also video, still and audio clips that can bring a subject to life.

We set out to compare two of the leading CD-Rom encyclopaedias from the point of view of an A-level student (Lily), and a journalist (Matt). We chose the Microsoft Encarta 95 (US version - see accompanying article) and the World Book Multimedia Encyclopedia.

Lily had to prepare for a mock United Nations Security Council meeting where she was to represent China. The debates were on nuclear proliferation and conventional weaponry. She set out using search modes looking just for "China". World Book proved quicker than Encarta. The interface is simpler, as it presents routes to everything from one screen (maps, history, geographical facts). Encarta takes a long time to load up information while World Book is almost instantaneous.

Also, when it came to printing, it was possible with World Book to highlight portions of text and print them using an on-screen button. Encarta, by contrast, forces you either to copy highlighted portions to a word processor document, or to print whole articles. But when it came to content, we really needed both CDs, because although World Book was far better on China, it did not have much on the UN or nuclear weapons, while Encarta had a lot of information about both of these.

Looking at the two encyclopaedias more generally, we found Encarta more of a multimedia experience. The Encarta atlas, for example, is not just a series of maps; it contains a "sights and sounds" feature that allows you to click on a place and immediately hear its name pronounced, see a photograph or video and hear native music.

Matt is researching an article on the Renaissance architect Andrea Palladio and looked him up in both encyclopaedias. While Encarta had a more extensive main entry, together with a photograph of Palladio's Villa Barbaro at Maser, the World Book had quicker, more extensive cross-references to other Renaissance architecture, and architects influenced by Palladio. It seems the World Book is better at presenting text-based information but has fewer audio-visual features.

A CD-Rom encyclopaedia is ideal for two purposes: easy cross-referencing and the addition of sound and video. But neither of these CDs does both equally well - although each does one superbly.

In sum, World Book is more efficient and Encarta is more fun. Surprisingly, the two CDs supplement each other more than they overlap. The good news is that they are cheaper and more useful than their printed counterparts; the bad news is that you have to buy both.