For many writers struggling for publication, advertising has proven a useful field (it does pay, after all): F. Scott Fitzgerald, Salman Rushdie, Dorothy Sayers, Don DeLillo, Joseph Heller and Helen Gurley Brown all worked as copywriters early in their careers—some with more success than others. Rushdie came up with "Naughty. But nice" cream cakes for Ogilvy & Mather; Sayers introduced "Just think what Toucan do" to Guinness and founded a dotty, fictional (and wildly popular) "Mustard Club"; and, thanks to Fitzgerald, streetcars in Iowa once ran with the promise "We keep you clean in Muscatine" sparkling on their sides.

Yet for all six, advertising was mostly just a means [...]