Everybody these days needs to know about international relations, because their workings shape all our lives. This book, explaining the particular significance of the international level of world politics, offers a comprehensive, accessible, and challenging overview of what is at stake, and what you need to know. World politics can be understood, simply, as Who Gets What, Where and How? (globally) to borrow a title from a famous old book by Harold Lasswell. International relations are a critical level in that business of determining who gets what across the world. Decisive things take place at the international level, and they directly or indirectly affect all our lives: war, trade, and the provision (or not) of human rights for example. This is why the practice of international relations matter. The reason academic International Relations matter is because it is the subject that asks the most fundamental questions about the politics of who gets what and how, and in the biggest political arena of all.