On Liberty is dedicated to one simple principle: that men and women should be free to do as they please, without interference from society or the State, unless their actions might cause harm to others. While many of his immediate prdecessors and contemporaries, from Adam Smith to William Godwin and Thoreau, had celebrated liberty, it was Mill who transformed the concept into a philosophy, claiming for it a central role in social policy and government and arguing for a redrawing of the line between the authority wielded by the State and the independence of the individual a view that continues to inform debates about personal liberty to this day.