Dell paperbacks accounted for nearly 20 percent of the paperbacks published between 1942 and 1962—a popular cultural phenomenon worthy of historical recognition. Putting Dell on the Map is an objective appraisal, rather than a court history of this major mass-market publisher. Early Dell books emphasized genre fiction—mysteries, romances, and westerns. Later the company published an important line of First Editions, which included the writings of authors such as Kurt Vonnegut, Jr., John D. MacDonald, Richard Jessup, and Robert Penn Warren. Dell also expanded its reprint efforts with Laurel Editions which emphasized quality reprints. In addition to their widespread popularity, Dell paperbacks are notable for their aesthetics. Dell's cover artwork alone spans a wide range of commercial art style from color airbrush front covers and distinctive back cover maps, to pulp and then neo-realist illustrations.