The Day of the Dinosaur is a science book by L. Sprague de Camp and Catherine Crook de Camp, illustrated with plates. It was first published in hardcover by Doubleday in 1968, and in paperback by Curtis Books in 1970 or 1971. A second hardcover edition was issued by Bonanza Books in 1985. The first chapter was reprinted as "One Day in the Cretaceous" in the de Camps's collection Footprints on Sand (Advent, 1981). Source: Wikipedia (en)