Book excerpt: Like Freakonomics, Dollars and Sex takes economics and converts it into a sexy science by applying the principles of supply and demand, and other market forces, to matters of love, courtship, sex, and marriage. As she does in her hugely popular blog, author Marina Adshade explores the marketplace for sex and love using research, economic analysis, and humor to reveal just how central the interplay of libido, gender, love, power, and economic forces is to the most important choices we make in our lives. Call it "Sexonomics."