Economics books full of “uncommon sense” are more common after the success of Freakonomics, but this rambling survey of hot-button and quotidian issues viewed from a libertarian economic perspective doesn’t measure up. Landsburg (The Armchair Economist) is sometimes pleasantly counterintuitive, but too often simply contentious. In using cost/benefit calculations to argue in favor of racial profiling or why we shouldn’t care about the looting of Baghdad’s museums, he strains to celebrate “all that is counter, original, spare and strange.” While positing multiple solutions to interesting problems, he forces logical readers to confront uncomfortable positions—as in the title essay, urging chaste citizens to sleep around, thereby diluting the pool of potential sex partners with AIDS. But the chapters typically conclude without resolution—at one point, the author shrugs: “It’s not easy to sort out causes from effects.” One suspects that a rival economist could swiftly debunk many of Landsburg’s arguments—for instance, his chapter praising misers (who produce but don’t consume) depends on the assumption that all resources are fixed and finite. By the time he makes the head-scratching case that “it’s always an occasion for joy when other people have more children,” the reader may be in the mood for some plain old common sense.