Jack Liebowitz, the comic-book publisher who made Superman an American institution, died on Monday in New York at the age of 100. In March of 1937, Liebowitz and business partner Harry Donenfeld published the first issue of Detective Comics (they took the initials and named their company DC Comics.) Liebowitz also started Action Comics, whose first issue, in June 1938, presented the story of the superbeing from Krypton. (Batman was introduced in May 1939.) The initial print run was 200,000 copies. That soon blossomed to about 1 million a month.