‘An Introduction to the Principles of Morals and Legislation’ is a book by the English philosopher and legal theorist Jeremy Bentham first published in 1789. Labelled as Bentham’s ‘most important theoretical work, ‘ it is where Bentham develops his theory of utilitarianism, in respect of ethical theory, and is the first major book on the topic. Bentham seeks to determine what a system of laws would look like if it was constructed on a purely utilitarian basis.