This introductory chapter explains the book’s big arguments: how Seneca is an important precursor for aspects of Shakespearean tragic characterization that seem presciently modern and how Shakespeare associates Senecan individualism with the loss of republican identity coordinates. Postromantic criticism has associated Shakespearean characterization with modern freedom, but it is indebted to Senecan tragedy where freedom from social constraint has a very different valence. In Seneca, freedom is associated with the loss of social coordinates and the potential for moral monstrosity, and that is part of what Shakespeare associates with personal freedom as well. This chapter traces the postromantic reception histories of Shakespeare and Seneca and shows that the emergence of an idea of Shakespeare as the poet of modernity has implied a downgrading of Seneca and therefore a willful occlusion of what is interesting about Senecan tragedy. It reviews how a revitalized interest in Senecan characterization supplements recent work on Shakespearean character.