First published in 1991, The Greatest Happiness Principle traces the history of the theory of utility, starting with the Bible, and running through Plato, Aristotle, and Epicurus. It goes on to discuss the utilitarian theories of Jeremy Bentham and John Stuart Mill in detail, commenting on the latter's view of the Christianity of his day and his optimal socialist society. The book argues that the key theory of utility is fundamentally concerned with happiness, stating that discussions of happiness have been largely left out of discussions of utility, it also argues utility as a moral theory, posing the question ultimately, what is happiness?