Scientific and historical in content, but intended for general readership, this is an account of the dinosaur from its first appearance on Earth to its sudden disappearance down an evolutionary "black hole" 65 million years ago. It conveys the geological timescale, evolution and habits of the creatures of the Mesozoic Era, and sheds light on the cause of their mysterious extinction. The book was originally published to accompany an international television series of the same name, presented by Walter Cronkite.