For anyone interested in the earth's structure and in knowing what made things as they are geologically speaking, this is topnotch. For anyone with a smattering of half forgotten knowledge along these lines, it brings it all into focus, ties up facts with things we see around us, and makes it a modern detective story of the earth's surface. Simple enough for the rank amateur, technical enough for the scientific minded. Should be brought to attention of schools and colleges and public libraries.