Western philosophy encompasses the philosophical thought and work of the Western world. Historically, the term refers to the philosophical thinking of Western culture, beginning with the ancient Greek philosophy of the pre-Socratics. Western thought concentrates principally on the history of the West and different issues confronting it. Political thought is of great importance. Plato was the first political philosopher in the Western world who lived through the period of the Peloponnesian War. This war almost changed the face of the existing empire and that of the succeeding others. Aristotle’s works are divided into logic, physical works, psychological works, philosophical works and works on natural history. Thomas Hobbes was an English philosopher whose political theories became the foundation of modern political thought. Hobbes gave us a theory based on how social and political order could be maintained in the world. John Locke was the father of classical liberalism whose tenet had a great impact on the period of Enlightenment, also known as the Age of Reason. In Rousseau’s ideal republic, the citizens legislate directly in accordance with the “general will,” the common good. To recognize this good, citizens must be trained in virtue and roughly similar in circumstances. For Mill, human happiness — the “greatest good” — is only possible in a free society where individuals are at liberty to make decisions about their lives. An annotated guide to the major political thinkers from Plato to Mao with a brief description of why their work is important and links to the recommended texts, and other readings. It focuses on the major works by key thinkers. This allows key themes (such as justice, the nature of the state, citizenship, and the role of religion) to be explored across the long-term development of western thought.