Crockett Johnson (October 20, 1906 – July 11, 1975) was the pen name of the American cartoonist and children's book illustrator David Johnson Leisk. He is best known for the comic strip Barnaby (1942–1952) and the Harold series of books, beginning with Harold and the Purple Crayon. From 1965 until his death Johnson created over a hundred paintings relating to mathematics and mathematical physics. Eighty of these are found in the collections of the National Museum of American History. Biography Born in New York City, Johnson grew up in Corona, Queens, New York, attended PS 16 and Newtown High School. He studied art at Cooper Union in 1924, and at New York University in 1925. He explained his choice of pseudonym as follows: "Crockett is my childhood nickname. My real name is David Johnson Leisk. Leisk was too hard to pronounce -- so -- I am now Crockett Johnson!" By the late 1920s, Johnson was art editor at several McGraw-Hill trade publications. With the Great Depression, Johnson became politicized and turned leftward, joining the radical Book and Magazine Writers Union. In 1934, he began his cartooning career by contributing to the Communist Party publication New Masses and subsequently joined the publication's staff, becoming its art editor and redesigning the magazine's layout. He remained with the magazine until 1940 and embarked on a career drawing comic strips in a series in Collier's magazine named "The Little Man with the Eyes". In 1942, he developed the Barnaby strip which would make him famous for the left-wing daily newspaper PM. In 1943 Johnson married writer Ruth Krauss. They had no children together, nor did they have children with their first spouses. Together they collaborated on several children's books. The children's book Harold and the Purple Crayon was published in 1955. He died of lung cancer in 1975. Children's books Johnson collaborated on four children's books with his wife, Ruth Krauss. The books were: The Carrot Seed, How to Make an Earthquake, Is This You?, and The Happy Egg. The books Harold and the Purple Crayon, Harold's Fairy Tale, and A Picture for Harold's Room have been adapted for animation by Gene Deitch. Mathematical paintings Johnson created his series of more than 100 mathematical paintings inspired by geometric principles and mathematicians. He painted layered geometric shapes in the paintings, based on classic mathematical theorems and diagrams in James Newman’s The World of Mathematics as