About 367 million years ago, during the Late Devonian period, a powerful force caused a mass extinction on Earth. It is estimated that some three-quarters of all living species did not survive. What caused this massive loss of species diversity, one of only five such crises in geologic history? Was it global cooling? A catastrophic impact, or several impacts? Palaeontologists cannot agree. Based on two decades of research this book reviews the many theories that have been presented to explain the event, considering in particular the possibility that the extinction was indeed triggered by the multiple impacts of extraterrestrial objects.
"McGhee thoroughly assesses knowledge about the Late Devonian mass extinction, during which at least 70 percent of species vanished. The text is so comprehensive and well written, though, that it could serve as a basic resource for thinking about all extinctions, mass or otherwise: the severity of the extinction, its duration, the various organisms affected, and likely causes. His approach is based first on a description of the evidence, and then on an analysis of the hypotheses [...] The objectivity of the book is enhanced by the author's willingness to even disagree with his own previous work [...] Anyone interested in extinctions should have this book."
"McGhee has written a science mystery about one of the major extinction events in the Phanerozoic in a well organized investigation of a mass murder [...] This book is a clear, concise treatment of a complex problem that deserves readership beyond individuals interested in extinctions or the Devonian."
– Jeff Over, State University of New York, Geneseo