Enter the simulated world of Sand Harvest and you take on the role of either a Tuareg nomad, a Songhai villager, or a government officer. You must battle against the encroaching Sahara while struggling to keep your animals fed and watered, grow sufficient food to feed the townspeople as well as your own community, and raise cash to pay the taxman. Success requires careful planning, and thoughtful decision making.

The actions of the characters are inter-related with natural conditions and world forces to determine the effect on desertification, the fate of crops, trees and water supplies; population, life expectancy and wealth; and to discover the success of government schemes.

At the end of every ear there is a report giving details of how all the variables have changed, comparing maps of the region before and after, and an explanation of what has happened. The software manages to present a lot of information in an understandable way. Annual reports can be printed for future reference.

The flexibility of the program is increased by the facility to change just about any variable influencing events, from the state of the exchange market to the level of annual rainfall.

Set-ups can be saved on disc and returned to later. A simple set-up is available at first enabling a feel for the simulation to be established quickly.

The program comes with a wealth of well-produced material - handbooks for the nomads, villagers and government officers as well as the organiser, with the relevant parts being freely photocopiable, and a wall chart with background information on Mali. The booklets are crammed with detailed local facts and provide a resource to make the simulation meaningful and captivating. Also included are many hints about introducing the program into the classroom and managing its use.

This package is a very valuable tool in the hands of the educationalist striving to encourage awareness of the world community. My only fear is that, if it is used superficially by people used to switch on and go software, it will be wasted: Sand Harvest deserves better than that.