The greatest dinosaur hunter of the twentieth century was Barnum Brown, who began his career at the American Museum of Natural History in 1897 as an assistant to Henry Fairfield Osborn. Brown traveled all over the world collecting dinosaurs and fossil mammals. Some consider him to be the last of the great dinosaur hunters.

Brown was always impeccably dressed, often wearing a tie and topcoat even in the field. He was a shrewd "horse trader" when it came to wheeling and dealing for fossil specimens. Many of Brown's greatest discoveries, including the first specimens of Tyrannosaurus rex ever found, are displayed in the Museum's Dinosaur Halls. Barnum Brown died in New York in 1963, at the age of 89.