Leviathan is a book written by Thomas Hobbes. The work concerns the structure of society and legitimate government, and is regarded as one of the earliest and most influential examples of social contract theory. Leviathan ranks as a classic western work on statecraft comparable to Machiavelli's The Prince. Written during the English Civil War (1642–1651), Leviathan argues for a social contract and rule by an absolute sovereign. Hobbes wrote that civil war and the brute situation of a state of nature («the war of all against all») could only be avoided by strong, undivided government. After lengthy discussion with Thomas Hobbes, the Parisian Abraham Bosse created the etching for the book's famous frontispiece in the géometrique style which Bosse himself had refined. It is similar in organisation to the frontispiece of Hobbes' De Cive (1642), created by Jean Matheus. The frontispiece has two main elements, of which the upper part is by far the more striking.