The books in the A True Book: Greatest Discoveries and Discoverers series feature discoveries within specific disciplines. Each volume includes an introduction to the field and its historical background, discoveries from recent decades, and possible future directions, as suggested by current research and technological developments. Undersea World offers a varied, informative view of underwater discoveries, from sunken treasure ships to Cleopatra's palace to the baffling circular patterns on the ocean floor that were later identified as the nests of puffer fish. Wide-spaced lines, large type, and many color photos give the pages an accessible look, even for readers who find the vocabulary challenging at times. As can be expected from the long-running, reliable True Books line, this series offers historical perspective and up-to-date information in a familiar format.