What effects do laws have? Do individuals drive more cautiously, clear ice from sidewalks more diligently, and commit fewer crimes because of the threat of legal sanctions? Do corporations pollute less, market safer products, and obey contracts to avoid suit? And given the effects of laws, which are socially best? Such questions about the influence and desirability of laws have been investigated by legal scholars and economists in a new, rigorous, and systematic manner since the 1970s. Their approach, which is called economic, is widely considered to be intellectually compelling and to...