The sheer comprehensiveness of Microsoft's top notch multimedia encyclopedia program makes it simply impossible to cover the full breadth of its work in one single review. Frankly, the numbers can get bewildering. This time around, over 130,000 articles, 24,000 pictures and thousands of multimedia clips (including fresh video content courtesy of a deal with the Discovery Channel) make up the core of the product, backed up by 1.8 million map locations, plenty of web links, a book of 20,000 quotations and a full dictionary and thesaurus. The complete reference guide? Quite feasibly.

What's remarkable about Encarta, though, is how well it all hangs together. There's a decent case for saying that the actual quality of the rival Encyclopaedia Britannica's content is better. However, Encarta is a PC product from the bottom up, and you can tell. It's staggeringly easy to get around, and with a comfortable, web-style browser holding things together, the interface very rarely gets in the way of the user going about their business. The whole presentation of the package is simply excellent, and some tweaks for the 2004 edition have improved things further.

Microsoft has correctly identified that one of the more troublesome areas of the program is the daunting nature of the sheer wealth of information contained within it. To combat this, the developers have introduced a brand new visual browser this time, which holds together quite well. For example, should you type 'computer' into the search engine, a screen is generated which allows you to delve straight into a main article, examine related topics or click for the visual browser.

Choose the latter, and the key items within the category of computing circle the screen, allowing you to simply click on one that interests you. It's a crude tool if you're looking for something reasonably specific, but great if you're looking for entry points into the data. When you do find things you're looking for, it's easy to jump back to them later, as you can bookmark anything you find of interest.

The visual browser isn't the only way to attack the data. More confident users can still jump in head first with the search tool, and the engine allows you to break down content into articles, images, and numerous kinds of multimedia. The Homework area, though, is inspired. From one easy screen, it's possible to access a wealth of tools to help in the researching and compiling of school work.

Back in this reviewer's day this kind of stuff meant sitting in a library full of BO trying to isolate one crucial sentence from a dog-eared book with the index long since ripped out of it. Here, the program's language, research, chart-making tools and curriculum guides are a click away, with not a sniff of BO within nasal distance. It's a terrific feature, and on top of the breadth and quality of Encarta's content, is one of the big contributory factors to why Encarta remains a superb piece of software.

The downsides? Well, it would be nice if you didn't have to sign up for the 'Plus' service to use the researcher tool properly, and there's the valid argument that the jump forward from year to year isn't that big. As Microsoft doesn't provide an upgrade pricing path with Encarta, you're hardly going to suffer if you stick with the 2003 edition for the time being.

Those who do decide to take the 2004 plunge, though, will be richly rewarded. We'd recommend that the extra money spent on the Premium Suite (costing £40 more than the £29.99 standard edition) is worth it, especially if you've got kids around, but whichever you plump for, Encarta 2004 is top-rate software, and the finest multimedia encyclopedia on the market.

As reference titles go, this is frankly brilliant. Easy to use, yet easy to lose hours using, Encarta 2004 is one of those rare examples of Microsoft at the very top of its game.