The Space Merchants - Frederik Pohl, Cyril M. Kornbluth

It is the 20th Century, an advertisement-drenched world in which the big ad agencies dominate governments and everything else. Now Schoken Associates, one of the big players, has a new challenge for star copywriter Mitch Courtenay. Volunteers are needed to colonise Venus. It's a hellhole, and nobody who knew anything about it would dream of signing up. But by the time Mitch has finished, they will be queuing to get on board the spaceships.