American comic book Kane and Bill Finger created Batman, who debuted in "Detective Comics" #27 (1939). The period from the late 1930s through roughly the end of the 1940s is referred to by comic book experts as the Golden Age of comic books. It featured extremely large print-runs, with "Action Comics" and "Captain Marvel" selling over half a million copies a month each; comics provided very popular cheap entertainment during World War II especially among soldiers, but with erratic quality in stories, art, and printing. In the early 1940s over 90 percent of girls and boys from seven to seventeen read comic books.
Comic book pseudonymous writer "Drake Waller" (Arnold Drake and Leslie Waller), penciler Matt Baker and inker Ray Osrin, touted as "an original full-length novel" on its cover. In 1971, writer-artist Gil Kane and collaborators devised the paperback "comics novel" "Blackmark". Will Eisner popularized the term "graphic novel" when he used it on the cover of the paperback edition of his work "A Contract with God, and Other Tenement Stories" in 1978. In 2017, the comic book market size for North America was just over $1 billion with digital sales being flat, book stores having a 1 percent decline, and comic book stores