Our ability to make choices is fundamental to our sense of ourselves as human beings, and essential to the political values of freedom-protecting nations. Whom we love; where we work; how we spend our time; what we buy; such choices define us in the eyes of ourselves and others, and much blood and ink has been spilt to establish and protect our rights to make them freely. Choice can also be a burden. Our cognitive capacity to research and make the best decisions is limited, so every active choice comes at a cost. In modern life the requirement to make active choices can often be overwhelming. So, across broad areas of our lives, from health plans to energy suppliers, many of us choose not to choose. By following our default options, we save ourselves the costs of making active choices. By setting those options, governments and corporations dictate the outcomes for when we decide by default. This is among the most significant ways in which they effect social change, yet we are just...