Butter, oil, tallow, lard, schmaltz--nutritionally crucial yet often villainized, at once rich yet cheap, fat is one of the most paradoxical categories of foods we consume. Shaping every cuisine on earth, fats in their various forms come with myriad cultural and symbolic meanings, playing an important role for a variety of people, from poor farmers to decadent aristocrats. Fats tells the story of this extraordinary substance--alternately reviled...