Religion is a phenomenon peculiar to human society. It came into being during the development of human spiritual activities even before human beings entered civilized society. Religion has exerted on the evolution of human history an impact that can not be neglected. In modern society, it is still an important spiritual and social force. The book has five parts:"General Concept of Religion","Religious Ideology","Religion and Social Life","Religious, History and Culture",and "Socialism and Religion". It elaborates the cardinal principles of religion on a ful lscale, with emphasis on relationship between religion and socialist society.