Voltaire called fanaticism the monster that pretends to be the child of religion. Philosophers, politicians, and cultural critics have decried fanaticism and attempted to define the distinctive qualities of the fanatic, whom Winston Churchill described as someone who cant change his mind and wont change the subject. Yet despite fanaticisms role in the long history of social discord, human conflict, and political violence, it remains a relatively neglected topic in the history of philosophy.In this outstanding inquiry into the philosophical history of fanaticism, a team of international contributors examine the topic from antiquity to the present day. Organized into four sections, topics covered include:Fanaticism in ancient Greek, Indian, and Chinese philosophy;Fanaticism and superstition from Hobbes to Hume, including chapters on Locke and Montesquieu, Shaftesbury, and Hutcheson;Kant, Germaine de Stael, Hegel, Nietzsche, William James, and Jorge Portilla on fanaticism;Fanaticism and terrorism; and extremism and gender, including the philosophy and morality of the manosphere;Closed-mindedness and political and epistemological fanaticism.Spanning themes from superstition, enthusiasm, and misanthropy to the emotions, purity, and the need for certainty, Fanaticism and the History of Philosophy is a landmark volume for anyone researching and teaching the history of philosophy, particularly ethics and moral philosophy. It is also a valuable resource for those studying fanaticism in related fields such as religion, the history of political thought, sociology, and the history of ideas.