The authors of Our Amazing Earth have once again taken a subject of presumably small general interest and made it readable and entertaining. This is more specifically a reference book, but it has whole sections that are entertaining and revealing. The function of rocks in the history of the earth, the classes and their component metal parts. The value of practical knowledge of rocks and the resultant adventure make this an important tool for the boys and girls who collect rocks (and their adult co-enthusiasts) and should give this a plus sale among collectors of all ages. The history of rocks, with their differing origins, and the important minerals that are found in rocks.