In a geologic instant, the K-T extinction event about 65 million years ago left Earth's skies empty of pterosaurs , extirpated the mosasaurs and their ammonite prey from the seas, and, of course, denuded the land of non-avian dinosaurs. But what if, by some fluke of evolutionary history, this catastrophe never happened and the global summer of the dinosaurs was allowed to continue? What might life on the planet look like today?

Thoughts of modern-day dinosaurs are the stuff of science fiction novels and B-movies --of unexplored islands and jungle plateaus teeming with vestiges of prehistoric life--but the Scottish geologist Dougal Dixon presented his own remarkably prescient and colorful answers to these questions in The New Dinosaurs: An Alternative Evolution . The speculative creatures within its pages--given whimsical names such as "Lank," "Zwim," "Lumber," and "Tubb"--were imaginative adaptations of Cretaceous life-forms modified to survive in a modern-world devoid of humans. After all, had dinosaur diversity not been rapidly winnowed down by extinction, mammals might have never gotten a shot to achieve ecological dominance. Our own evolution could have been cancelled.