The ground yields many substances to make life safer and more comfortable. How ores are mined, iron smelted, metals made into alloys, tell how man has taken advantage of this natural bounty. Rocks are put to use in many fascinating ways and petroleum requires a special handling to become gasoline. The earth also yields fossils enabling man to reconstruct history. This book is uneven in terms of illustrations. Some are lifeless-similar to the previous titles, others are strong and eye-catching with a decided original flair.