Populorum progressio is the encyclical written by Pope Paul VI on the topic of "the development of peoples" and that the economy of the world should serve mankind and not just the few. It was released on March 26, 1967. It touches on a variety of principles of Catholic social teaching: the right to a just wage; the right to security of employment; the right to fair and reasonable working conditions; the right to join a union and strike as a last resort; and the universal destination of resources and goods.