When CNBC reporter Rick Santelli angrily called for a 'tea party' from the floor of the Chicago Mercantile Exchange in February 2009, the specific target of his wrath was a new government program to help distressed homeowners with crushing mortgages. Yet there was also a more general target: the government's increasing involvement in the economy following the 2008 financial crash. By spring 2009, the state had extended its reach deep into the nation's private banking system, assumed control of a significant portion of the auto industry, and passed a stimulus plan of nearly a trillion dollars. Advocates of limited government saw this as disastrous, and Santelli's impassioned rant captured their reaction perfectly. Santelli was also drawing from an American political tradition with deep roots. Popular hostility toward an overweening state extends back to the nation's founding, with critics of the state always seeing it as an enemy of liberty. In the mid-twentieth century, this longstanding impulse evolved into both a coherent political philosophy and a political movement: libertarianism. Most tend to associate libertarianism with a two central principles. The first is the sanctity of personal freedom, a concept which encompasses everything from reproductive rights to drug legalization to gay rights to banning military drafts. The second is the superiority of free market capitalism over all other forms of economic systems. For such a system to function effectively, the role of the state in the economy must necessarily be minimal. Yet as Jason Brennan shows in this highly engaging and wide-ranging primer, libertarianism is far more than this. He covers its history, its philosophical tenets, disputes within the movement, the views of its critics, and its current political fortunes. He also focuses on specific issues like altruism to immigration. Finally, he looks beyond the U.S. and shows how libertarianism has attracted followers in liberalizing states throughout the world. In the last few years, libertarianism's popularity has grown at an explosive rate. In a recent CNN poll, 63 percent of Americans agreed that the government is doing too much and that more issues should be left to individuals and businesses. In that same poll, 50 percent said that government should not try to promote traditional values. Ron and Rand Paul's success and the Republican's dogmatic opposition toward all forms of government intervention also speak to libertarianism's increasing influence. For anyone interested in the philosophy and the movement,Libertarianism: What Everyone Needsto Knowis the perfect introductory overview.