Nudge: Improving Decisions About Health, Wealth, and Happiness by Richard H. Thaler and Cass R. Sunstein is a guide to policy makers, teachers, parents, and others who want to “shape” behavior. Thaler and Sunstein start with simple examples like placing healthy food a eye level in a food line and move on to complex 401K decisions. If you’re interested in “nudging” someone in your life to take a particular action, this is the place to start.