A history of species extinctions, their causes and the looming sixth extinction. Explores the history of this search, its subjects, its controversies, its current conclusions, and their implications for our efforts to preserve Earth's biodiversity. It explains what extinction is, what causes it and whether it is preventable, and by comparing past geological extinction events, it aims to predict what will happen in the future.

What is extinction? -- Evolution, fossils and extinction -- Patterns in extinction data -- Kinds of extinction -- Causes of extinction -- Precambrian and Cambrian extinctions -- The End-Ordovician extinctions -- The Late Devonian extinctions -- The Late Permian extinctions -- The Late Triassic extinctions -- The End-Cretaceous extinctions -- The Palaeogene extinctions -- The Neogene and Quaternary extinctions -- The modern and future extinctions -- Summary and conclusions.