Patterson, who can count his best sellers by the dozens (take that, Dan Brown), is the Henry Ford of the literary world. Known for popular series such as Maximum Ride and Alex Cross (who has a Ph.D. in psychology from Johns Hopkins, by the way), he often writes with collaborators. As he told Time magazine, he delivers an outline, they write a first draft, and he polishes. His new deal calls for 10 thrillers, one non-fiction work and six novels for kids by 2012.
Patterson doesn't get a lot of respect for his work -- I've seen it referred to on LibraryThing as "Extruded James Patterson Product(TM)". I do give him credit for openly crediting his collaborators (even though it's clear form his website and marketing materials that his is the name that counts). And he certainlyt is a genius for figuring out what a large segment of readers want.