Historically, children's book illustration wasn't its own field. Art schools did not offer programs specializing in it. There were no galleries devoted to it. And so illustrators often fell into this work by chance. Wanda Gág and Robert McCloskey (the creator of Make Way for Ducklings and Homer Price) were aspiring artists and printmakers. Clement Hurd was a painter who would have preferred a career in set design. All three became children's book illustrators because an opportunity came along that offered the prospect of making a little money.

Norman Rockwell, by contrast, was an established painter when he was commissioned to illustrate Mark Twain's Tom Sawyer. His style was viewed as natural and optimistic enough to be a good fit for Twain's homespun, folksy writing. The writer and painter would both go on to darker and weightier work in their later years.