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.
Jan (comic book writer) down in 1985, Jan, together with many other comic book writers, had to do work for other editorial companies. Jan published his first (and only) erotic comic 'Laszivia' in Norma Editorial, and created characters such as 'Cab Halloloco' and 'Los ultimos de Villapiñas' for the Jauja comic magazine. The character 'Superioribus', drawn for the editorial Forum, is also a superhero parody. In 1987, Ediciones B began publishing a Superlopez magazine. In this way Jan can continue working on this character till now, with a few other contributions from time to time to other magazines, such as the characters "Pum Tarrota"