This book argues that there are basic positive duties of justice to help eradicate severe global poverty; that global egalitarian principles are also reasonable even if they cannot be fully realized in the short term; and that there are dynamic duties to enhance the feasibility of the transition from global poverty to global equality in the face of nonideal circumstances such as the absence of robust international institutions and the lack of a strong ethos of cosmopolitan solidarity. The very notion of feasibility is crucial for normative reasoning, but has received little explicit philosophical discussion. This book offers a systematic exploration of that concept as well as of its application to global justice. It also arbitrates the current debate between humanist and associativist accounts of the scope of distributive justice. Drawing on moral contractualism (the view that we ought to follow the principles that no one could reasonably reject), this book provides a novel defense of humanism, challenges several versions of associativism (which remains the most popular view among political philosophers), and seeks to integrate the insights underlying both views.