The Dinosaur Systematics Symposium was held June 3–5, 1986, at the Tyrrell Museum of Palaeontology, Drumheller, Alberta. There were over sixty-five individuals in attendance, with twenty-eight papers given. Of these, nineteen are presented in this volume. The purpose of the symposium was to examine sexual dimorphism, ontogeny, individual variation, and any other factors that may influence the taxonomic designation of a particular specimen of dinosaur. The symposium was the second in an unstructured series on aspects of dinosaurs as living creatures, the first being held the previous month (Gillette and Lockley 1989). Systematics was selected as the theme because all other studies essentially build on systematics.

The success of the symposium was made possible by the friendly attitude of all the participants. Although there were disagreements, there was no hostility. As is typical for dinosaur paleontologists, their passion for the subject led to numerous discussions, well into the evening, over beer at the local watering hole. Thus, it is not surprising that one participant called the symposium “the Woodstock of dinosaur paleontology.”

Because so much current systematic work on dinosaurs is being done on Upper Cretaceous material, the symposium and this volume are dedicated to Charles Mortram Sternberg (1885–1981). Although some of the species he established are shown to be invalid by papers in this volume, he did try to recognize variation in the material he studied.