The author was formerly the chief of the Division of Geophysics, Coast and Geodetic Survey and his primary personal interest was earthquakes and all that pertain to them -- factual history, legends on how they happen and how they're tracked. In condensing his fund of information for young readers, Roberts has organized his material to hold interest. Scientific and geological material is balanced with the odd and interesting sidelight. The glimpses provided of seismology and its importance is good career background information. Altogether, the book is an excellent introduction to the rocky area of other geological materials and phenomena.