Leviathan is a book written by Thomas Hobbes and published in 1651. It is one of the most important works in political philosophy and is considered a cornerstone of modern political thought.

The main argument of Leviathan is that humans are fundamentally selfish and violent, and that without a strong government to control them, they would inevitably descend into a state of chaos and conflict. Hobbes famously characterized this state as "the war of all against all."

In order to avoid this scenario, Hobbes argued that individuals must surrender their natural rights to a sovereign authority. This sovereign, which Hobbes called the Leviathan, would have absolute power to enforce its will upon the people, and in exchange would provide them with security and protection.

Hobbes believed that the ideal form of government was an absolute monarchy, where the sovereign's power was not limited by any laws or institutions. He argued that any attempt to limit the power of the sovereign would be doomed to failure, as it would only lead to the re-emergence of the state of nature and the breakdown of society.

Leviathan is also notable for its contributions to social contract theory, which argues that individuals enter into a contract with their government in order to protect their rights and maintain order in society. Hobbes' social contract theory was influential in the development of political thought and continues to be studied and debated today.