This chapter examines the theories that have been advanced to explain the conflict and how they have been translated into the design of political institutions. It examines the development of the theory of consociationalism and how it has been woven into the intellectual debate about the nature of the Northern Ireland conflict. The chapter discusses the various attempts to construct institutions to resolve the conflict leading up to the 1998 Belfast Agreement. It focuses on the 1998 Agreement and its aftermath with the problems of implementing the main terms of the Agreement. The chapter considers the evolution of political thinking about possible solutions to Northern Ireland in the three decades leading up to the 1998 Belfast Agreement. It provides a core empirical base for anyone interested in the dynamics of public opinion in Northern Ireland. The chapter presents the introduction to the subsequent chapters of this book.