One of the most influential American cartoonists to emerge in the World War II era, Eisner (b. 1917) initially made a splash with his detective/adventure strip The Spirit in 1941. Created for the Sunday supplements, The Spirit stretched the boundaries of its genre through inventive graphic design and digressive storytelling. In 1978, after a long absence from comics, Eisner returned with a much different work, A Contract with God, a long realistic story for which he coined the term "graphic novel." This and many of his subsequent books focused on the lives of immigrants in his native New York City. Eisner has also taught comics, and his book Comics and Sequential Art was the first substantial theoretical study of the medium.