A scholarly survey of the seven extant sea turtle species with an enormous amount of information focused on the author's work' mainly on islands off the Australian coast. The sea turtle -- a ""living dinosaur"" -- has not changed its appearance substantially since the Age of Reptiles 90 million years ago, and the first section is concerned with a biological and evolutionary profile, followed by a survey of living species. He discusses turtle behavior, the most fascinating part for the layman, including among other matters the peculiar nesting habits of the lumbering creatures -- the female lays her eggs in the sand after laboriously constructing a nest, then returns to the sea. Even an academic like Bustard breaks into a kind of reptilian poetry upon witnessing the ancient and bizarre ritual: ""As we watch the moon's reflection on the water, a silvery shape becomes visible . . . ."" After an exhaustive review of highlights of the life cycle, Bustard reviews his own research in the field and summarizes conservationist efforts with a strong plea for saving these ""enormous, shy and completely harmless relics of a bygone age.