Let's begin by addressing the most obvious question: given the vast number of books published on political science every year, why would the Association for Politics and the Life Sciences (APLS) and its journal Politics and the Life Sciences expend time, energy, and resources publishing a multiple-author analysis of a series of books that contain little (if anything) about the life sciences, Darwin, or evolution? The answer is that Cass R. Sunstein's recent research on “nudge science” provides an excellent opportunity for APLS to expand its commitment to interdisciplinarity, especially its long-standing interest in behavioral economics. Sunstein, a prolific author, has written many books and scholarly articles defending “libertarian paternalism.” Libertarian critics have long argued that the conjunction of “libertarian” and “paternalism” is oxymoronic and that the “liberty principle” or the “principle of autonomy” excludes paternalistic intervention on behalf of rational, competent adults. Over the years, with varying degrees of success, Sunstein has addressed many, if not most, lines of criticism emanating from the political left and right. Like many scholars, his views have evolved over time based on that criticism. This introductory essay will focus on some of the more enduring elements of the conceptual framework and issues that underlie nudge science in the larger context of behavioral economics, including choice architecture, political bans and mandates, political nudges, ethics, and paternalistic intervention.