There are certain things in life you don’t know you need until you’ve got them. Then, of course, you can’t do without them. For some people, this CD-Rom could be one of them.

Quite simply, Planet Earth is an archive of environmental awareness.

It has two main elements: 2,600 articles taken from The Times since the early 19th century, and more than 1,000 colour photographs.

When these are accessed through a carefully cross-referenced indexing system, you have a comprehensive guide to the environmental issues that have been exercising our minds over the past 200 years or so.

It takes only a few minutes to get used to getting around the disc, and thereafter you can be lost in a wealth of articles. For teachers, it is a major source of background information.

The facts and figures can be found, and also the opinions of the day.

This second point is fascinating; you can trace changes of attitudes over time with topics such as nuclear power, deforestation and alternative fuels.

For Pounds 59.99 (educational price) you need to be aware of what you’re getting.

First, you are buying a good archive and some excellent screen design features. You also have simple print and store features to save you revisiting the same parts of the program twice.

Be warned, however, that there is a disproportionate focus on issues affecting Britain - and the program lacks a simple word search function, which might have been expected. The index screen contains major topics only; beyond that you have to go searching for articles that mention, say, your home town or your favourite polluter.