This chapter sets out the logic of the practical pursuit of global justice through global democratization. The theory rests on the concept of formative agents of justice, who shape what justice should mean in specific contexts, and how it should be sought. The chapter analyses formative agents’ role in bridging the gap between democracy and justice, thereby situating this book’s contribution within existing debates on international ethics, global justice, global governance, and deliberative democracy, before outlining the ways deliberative democracy can promote global justice. This approach meets challenges arising from the irreducible disagreement over the content of justice in both theory and practice, and from the need to identify who exactly should be responsible for the advancement of justice. The theoretical arguments of the book will be informed by and applied to the process that yielded the Sustainable Development Goals, and to climate governance inasmuch as it takes on climate justice. These two cases are introduced, along with a discussion of the kinds of justice they promote, ignore, and obstruct. Chapter 1 concludes with a brief overview of the remaining chapters.