The concept of law lies at the heart of our social and political life, shaping the character of our community and underlying issues from racism and abortion to human rights and international war. But what actually is law? Is it just a set of rules, or something much more than that? And what is its role in society? This Very Short Introduction examines the central questions that have fascinated lawyers and philosophers - and anyone - who ever wondered about law's relation to justice, morality, and democracy.