John H. Ostrom
Ostrom is Professor Emeritus of Geology and Geophysics at Yale University. He has led many expeditions to explore areas for dinosaur remains, including the discovery of Deinonychus in 1964.
He is also well known for his progressive theories on the physiology of dinosaurs - together with Robert Bakker - considering that dinosaurs may have been agile warm-blooded creatures.
He was also the first to place Hadrosaurus on dry land - not a swamp creature - by examining, amongst other things, plant material found in association with it. He brought back Huxley's theories on birds being descendants of the dinosaurs.