Are there any universal entities? Or is the world populated only by particular things? The problem of universals is one of the most fascinating and enduring topics in the history of metaphysics, with roots in ancient and medieval philosophy. This collection of new essays provides an innovative overview of the contemporary debate on universals. Rather than focusing exclusively on the traditional opposition between realism and nominalism, the contributors explore the complexity of the debate and illustrate a broad range of positions within both the realist and the nominalist camps. Realism is viewed through the lens of the distinction between constituent and relational ontologies, while nominalism is reconstructed in light of the controversy over the notion of trope. The result is a fresh picture of contemporary metaphysics, in which traditional strategies of dealing with the problem of universals are both reaffirmed and called into question.