Thomas Hobbes (1588-1679) is widely held to be one of the most important thinkers in the history of philosophy. His contributions to ethics, political philosophy and psychology in particular were hugely innovative and he was regarded by his contemporaries as a major intellectual figure. This comprehensive and accessible guide to Hobbes's life and work features 120 specially commissioned entries written by a team of leading experts in the field of seventeenth-century philosophy and political thought, covering every aspect of Hobbes's ideas. The Companion presents a comprehensive overview of the major themes and topics in Hobbes's work, in particular within the fields of language, political philosophy, moral philosophy and psychology, religion, law and science. It concludes with a thoroughly comprehensive bibliography of primary and secondary sources. This is an essential reference tool for anyone working in the fields of seventeenth-century philosophy and political theory.