One of the greatest challenges in the twenty-first century is to address large, deep, and historic deficits in human development. A crucial question we explore in this book is how democracy – with all of its messy, contested, and time-consuming features – works to advance well-being and improve citizens’ lives. Broad evidence demonstrates that democracies provide more public goods and higher standards of living, on average, for citizens than authoritarian countries (Przeworski et al. 1999: 264–265; Lake and Baum 2001; Besley and Kudamatsu 2006; Brown and Mobarak 2009; Acemoglu et al. 2013; Harding and Stasavage 2014; Hodgson 2017; Gerring et al. 2015). We move beyond the conventional explanations – elections, political competition, and partisanship – to develop theory connecting core dimensions of democracy – participation, citizenship, and an inclusive state – to improvements in well-being. In doing so, we illuminate how these dimensions form “pathways” that help citizens and governments achieve better human development outcomes.