This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book deals with what is probably the most basic, but most fundamental, truism in strategy: it is a human activity. It addresses the human dimension through two main areas of study: culture and psychology. The book explores the increasingly challenging area of ethics as applied to war. It outlines the origins and development of the revolution in military affairs hypothesis. The book discusses the surprisingly neglected field of intelligence in the conduct of strategy. It discusses how theorists have depicted the relationship between intelligence and strategy and how their work may help policymakers organise intelligence services to keep strategists as well informed as possible. The book focuses on that most basic of geographic expressions of military power: land warfare. It also deals with sea power, which is an area of strategy afflicted by definitional problems.