This is especially true of nonfiction. One of the biggest flocks right now, for instance, is following Jon Krakauer's Into Thin Air , a firsthand account of the Mount Everest climbing disaster of 1996, which was a runaway bestseller last year. Right with it at the front of the formation are Sebastian Junger's maritime disaster, A Perfect Storm , and Krakauer's own earlier wilderness tragedy, Into the Wild , which got a retroactive lift from Into Thin Air . But the cachet of book publishing is still the cachet of art. The whole point of writing and printing a nonfiction book should be to tell people something new, to pick a subject out of the great wide ignorable world and express something about it that's worth reading.
Publishers see flocking as a necessity because books are notoriously unpredictable sellers.
The only available data for forecasting the sales of future titles are the sales of past titles. So to some extent, almost all publishing is copycat publishing. Ninety percent of all acquisitions in publishing is . . . You have to sell these books to bookstores, and bookstore owners see millions of copies of Krakauer flying out the door. To be fair, when they're not being used to sell apples as oranges, such comparisons are of value to the reading public.