SEND AWAY

Deserts--some cold, some hot, some rocky, some sandy--make up about a third of the Earth’s land surface. Not much compared with Mars, which is all desert except at its poles. Still, before we get too smug, we should consider that human activity and other factors are helping deserts grow on Earth.

You can learn this and most things you would want to know about deserts from an excellent 60-page booklet put out by the U.S. Geological Survey. Called “Deserts: Geology and Resources,” it describes the types of deserts, how they form and their features.

The booklet also is filled with beautiful photos showing the dramatic variation among the Earth’s deserts, along with charts and maps. In other words, everything you could need for a school report on the subject.

And it’s free, by writing for publication number 94-0041 to U.S. Geological Survey, Branch of Information Services, Box 25286, Denver Federal Center, MS 306, Denver, CO 80225. Don’t wait for a school assignment to place your order; it takes about a month to receive your booklet.