Despite a long history of external threats and internal strife, the Roman Catholic Church remains a vast and influential presence in our modern world. But what were its origins, and how has it changed and adapted over the centuries? After Pope Benedict XVI dramatically resigned in early 2013 (the first Pope to resign since the fifteenth century), and Pope Francis was elected, many wondered what direction he would lead the Church in, and whether the Church could modernise in the face of the demands of our world. In this Very Short Introduction, Gerald O'Collins covers the history of the Catholic Church, and considers some of the key issues facing Catholicism today, such as the catastrophic revelations about clerical child abuse, the impact of the growth of Islam, and the destruction in the Middle East of ancient Christian church communities. He also shows how Catholics are being increasingly challenged by an opposition between their traditional Christian values and rights which are endorsed by the secular world, such as the right to physician assisted suicide or same-sex marriage, and considers the future for the largest and oldest institution in the world.