The Road to Serfdom by F. A. Hayek (1994, Paperback, Anniversary)

Terrific book. This is often leading the top ten on any conservative / libertarian reading list, and it is obvious why. While it is a bit dated, it is a point-by-point assessment of the dangers of collectivist thinking (statist thought), and it applies as much or more to modern America as it did at the time of printing (e.g. Hillary and Obama). In sum, the theory of the book is that collective / socialist thought, in addition to being well-meaning but ineffective in practice, is dangerous because it tends toward totalitarianism (using Germany from 1900-1940 as an example of a growing Socialist state reaching a crescendo of totalitarian control in the form of Naziism). Very good read.