Catholic Social Teaching is often described as the Church's "best-kept secret", and with good reason. As a parish priest, I have often been struck that even the most devout and theologically well-read Catholics know little of the great social encyclicals. They may be passionate about abortion, but far less interested in questions such as the fair wage. When I write about Catholicism and the EU - which was founded with the help of Catholic politicians such as Robert Schuman - I am sometimes told: "The Church should keep out of politics." But that has never been the case.