IN MAKING THE LIST, his 2001 book about best sellers, former Simon & Schuster editor in chief Michael Korda recalls that the publishing house once commissioned a study of which books made the most money. After a detailed presentation, the consultant said to the editors, "Do you guys realize how much money the company would make if you only published best sellers?" He might as well have told them that they'd do better playing the lottery if they picked the right numbers. Trends come and go, but the best seller remains essentially serendipitous. An editor can be no more certain of finding the next one than a writer can be assured of writing it. "As a rule of thumb," writes John Sutherland, an English scholar who has studied the phenomenon, "what defines the bestseller is bestselling. Nothing else."