“[M]uch in the way it has cultivated its image as a counterintuitive purveyor of Isaac Mizrahi clothes or Michael Graves tea kettles, Target has been building itself into a tastemaker for books. Through its book club, as well as a program it calls Bookmarked Breakout, both started in 2005, the company has highlighted largely unknown writers, helping their books find their way into shopping carts filled with paper towels, cereal and shampoo.”