This chapter introduces and defends the themes around which the Handbook has been constructed: the importance of an engagement between International Political Theory (IPT) and “real-world” politics, and the need to establish links between IPT and the empirical findings of International Relations scholars. The “new realist” critique of “moralism” is examined along with the more general critique of ideal theory, and both are found to hit a very narrow target. The conventional distinction between “critical theory” and “problem-solving theory” is also challenged, and each is defended as an equally important, albeit different, stage in the life of a theory. The second half of this chapter sets out the principles upon which the Handbook is organized, and provides a guide to each section and chapter.