Voltaire is one of the greatest thinkers of the 18th century, poet, playwright, publicist, and historian. He was called the "king of public opinion." In his sharp articles and pamphlets, Voltaire protested against wars, religious fanaticism, persecution of dissenters and advocated education and social freedoms. Voltaire’s “Treatise on Tolerance,” written two and a half centuries ago, still sounds fresh and topical today, since its main theme—tolerance for dissidents—is relevant at all times. Tolerance is one of the fundamental principles of humanity, the author believes, and calls on people to be guided by this principle in their actions. Like other books in the “Great Ideas” series, the book will be simply irreplaceable in the library of students of the humanities, as well as for those who want to get acquainted with key works and ideas of world philosophy and culture.