Maxwell Reed does not sugar-coat his scientific content, but he does make it thoroughly readable and clear cut. This time he answers lots of questions that I've never had answered more satisfactorily. Why is the sky blue? What makes the colors of the sunset? What causes rainbows, shadows, reflections, etc.? There are other things that have been done as well elsewhere, such as what makes the ocean salt, what creates hills and mountains, deserts and volcanoes. But Reed will probably introduce the subject to the sub-teen age group for the first time.