Download the book Sir Richard Owen coined the term "dinosaur" ("Terrible Reptile" or "Fearfully Great Reptile") in the 19th century. When Harry G. Seeley, a student of law at that time, attended a lecture on flying reptiles, his interest in paleontology was piqued, and he pursued paleontology for the remainder of his life. He determined that dinosaurs could be divided into two groups, the lizard-hipped dinosaurs and the bird-hipped dinosaurs. He is also credited with characterizing flying dinosaurs as warm-blooded active flyers rather than cold-blooded passive gliders. His popular book on the flying dinosaurs, Dragons of the Air, is a comprehensive treatise on the structure, classification, and possible evolutionary origins of the Pterosaurs as well as their relationship to birds.