Each of us can call to mind a clear image of many dinosaurs. That’s surprising, since no human ever set eyes on one. The images that we have derive largely from the work of one man, Charles R. Knight.

A gifted wildlife painter at the end of the 19^th century, Knight was on the staff of the American Museum of Natural History. The museum’s president sent him to soak up the current knowledge on paleontology from the eminent fossil hunter Edward Drinker Cope, who was dying. Knight emerged from his studies with images of the dinosaurs so lifelike, you can practically smell their breath. He painted murals in America’s biggest natural history museums and helped shift the presentational style from trays full of bones to environments that attempted to recreate the world of eons past. Notwithstanding some changes in the science, Knight’s images hold up today as our best imaginings of these creatures.

And it was those images that influenced the pop culture of the 20^th century. Richard Milner, author of Charles R. Knight: The Artist Who Saw Through Time, details how they crept into representations like Gertie the dinosaur, the star of the first cartoon movie; a novel by Arthur Conan Doyle; the blockbuster Jurassic Park; all the way down the evolutionary ladder to the big purple dinosaur on TV. Perhaps Knight did his work too well, inspiring a fetish for these extinct creatures. But paleontologist Paul Olsen says it was essential for the development of science. “When you can't see the animal alive in front of you, you have to have some kind of mental model of what it's like — and that is in fact what an artist does ... If you don't communicate the information, it does not exist.”

Slideshow: Charles R. Knight's dinosaurs