In the 18th century, ground-breaking discoveries in science bought about a vast moral, scientific and political upheaval, in which the age-old authority of the church was challenged. It was thought that by means of scientific endeavor, the essential order of Nature could be systematically explained, its processes mastered and its secrets revealed, to enable man to explain the world and change it for the better. This book explains the background and implications of this momentous age. It examines three giants of the Enlightenment - Voltaire, Diderot and Rousseau - and also looks at David Hume, Adam Smith, Samuel Johnson, Immanuel Kant, Benjamin Franklin and Thomas Jefferson.