Unknown & John Locke 
Two Treatises of Government 

In this influential book, John Locke outlines his theory of government. In the first part, he refutes the idea that there is any such thing as the divine right of kings. In the second, he argues that nature created men equal, and that any system of government must be based on that equality. This is a must-read text for any one who wants to understand the history of ideas.