Paul O. Zelinsky (born 1953) is an American illustrator and writer best known for illustrating children's picture books. He won the 1998 Caldecott Medal for U.S. picture book illustration, recognizing Rapunzel. His most popular work is The Wheels on the Bus, a best-selling movable book.Zelinsky had been one Caldecott runner-up in 1985, 1987, and 1995, the latter for Swamp Angel by Anne Isaacs (Dutton, 1994).