Bound collection of comic strips, usually in chronological sequence, typically telling a single story or a series of different stories. The first true comic books were marketed in 1933 as giveaway advertising premiums. By 1935 reprints of newspaper strips and books with original stories were selling in large quantities. During World War II comics dealing with war and crime found many readers among soldiers stationed abroad, and in the 1950s comic books were blamed for juvenile delinquency. Though the industry responded with self-censorship, some adventure strips continued to be criticized. In the 1960s comic books satirizing the cultural underworld became popular, especially among college students, and comic books have been used to deal with serious subjects (e.g., Art Spiegelman's Maus books, about the Holocaust). Japanese comic books (manga), with their great variation in content and affect, have achieved wide popularity. Today comic 'zines represent a thriving subculture.