The document provides background information on key figures of the Enlightenment period in the 18th century. It discusses their ideas and contributions, including John Locke's views on human understanding, Isaac Newton's laws of physics and application to society, Montesquieu's separation of powers model of government, Voltaire's criticism of Christianity and support for religious tolerance, and Denis Diderot's Encyclopedia that aimed to change the way of thinking. The Enlightenment was a philosophical movement defined by the use of reason and natural laws to understand humanity and society.