"One of my favorite subjects for paintings was the big top circus", Bill Peet wrote in his autobiography. In the early twentieth century the circus was a major form of entertainment. It arrived on trains pulled by steam locomotives, which Bill Peet also loved. He was an animal lover and the circus was a great opportunity to see all kinds of animals. He loved all the activity of setting up the big top and other tents. Five of his books are based in circuses: Chester the Worldly Pig, Ella, Encore for Eleanor, Pamela Camel, and Randy's Dandy Lions.

When he was working on "Dumbo", he went to the circus to sketch its people, animals, tents and wagons.

He loved the behind-the-scenes activities; the struggles to get the tents up and prepare for the shows.

He also used a little box camera to document scenes for future reference. Below are some of the photographs he took in the late 1930's and early 40's.

Bill Peet loved draft horses, which were still used extensively in circuses in the 1930's. The main character in the story, Cowardly Clyde, was such a horse.