Catholic Social Teaching (CST): Catholic Social Teaching (CST) is grounded in the Bible and developed in the light of Church teaching and the experiences of people in many different cultures. In analysing social, political and economic issues in the contemporary world, CST provides a set of key principles which can be used to evaluate situations, policies and approaches used in contemporary society from a Catholic perspective. CST also provides guidelines for action. Catholic Social Teaching (CST), the formal teaching on social justice which exists within the Church, is developed through a series of documents beginning with Pope Leo XIII's Rerum Novarum (1891) 'Of New Things' which examined working conditions in industrialised countries and insisted on workers' rights; to Laudato Si' (2015) 'On Care of Our Common Home' which Pope Francis addressed to “every person living on this planet”. In Laudato Si', Pope Francis asks all people to pay particular attention to the environment asking “What kind of a world do we want to leave to those who come after us? ”Over the past 125 years since CST emerged, a number of key themes or principles have been identified in the documents of Catholic Social Teaching. Some scholars list ten principles; others list six principles. The two lists mean that some principles are grouped together. Each Catholic social teaching theme is connected to other Catholic Social Teaching themes and together they provide a set of signposts and questions to guide us in the choices we make and how we think and act towards addressing justice in our world.