For the physicist, see Theo Geisel (physicist). Theodor Seuss Geisel (/ˈsɔɪs/ /ˈɡaɪzəl/; March 2, 1904 – September 24, 1991) was an American writer, cartoonist, animator, book publisher, and artist best known for authoring children's books under the pen name Dr. Seuss (/suːs/).