Leo Lionni (May 5, 1910 – October 11, 1999) was an author and illustrator of children's books. Born in the Netherlands, he moved to Italy and lived there before moving to the United States in 1939, where he worked as an art director for several advertising agencies, and then for Fortune magazine. He returned to Italy in 1962 and started writing and illustrating children's books. In 1962 his book Inch by Inch was awarded the Lewis Carroll Shelf Award.
"Art director of N.W. Ayer & Son, was born in Watergraafsmeer, Holland . . . He has shown paintings and drawings in exhibitions abroad, and some of his drawings have been selected for the permanent collection of the Philadelphia Museum of Art." (Modern Art in Advertising).