Almost 115 years after the publication of Rerum Novarum the Church sought to compile and summarize its modern social teachings. In 2004 the Pontifical Council for Justice and Peace published Compendium of the Social Doctrine of the Church to summarize and restate the Church’s social teachings to serve as a reference for all Catholics.
Pope Benedict XVI wrote the encyclical Deus Caritas Est in 2005 about God’s love for humanity. In a world where the name of God is sometimes associated with vengeance or even hatred, Benedict seeks to speak of the limitless love that God lavishes on humanity.
The encyclical is divided into two parts. The first section discusses God’s love and the reality of human love. In the second part, Benedict focuses on the commandment to love one’s neighbor especially the laities role in creating a just society.
Charity in truth, to which Jesus Christ bore witness by his earthly life and especially by his death and resurrection, is the principal driving force behind the authentic development of every person and of all humanity. Love — caritas — is an extraordinary force which leads people to opt for courageous and generous engagement in the field of justice and peace. It is a force that has its origin in God, Eternal Love and Absolute Truth. Each person finds his good by adherence to God's plan for him, in order to realize it fully: in this plan, he finds his truth, and through adherence to this truth he becomes free (cf. Jn 8:22).
In Laudato Si, a letter addressed to all the people of the world, Pope Francis presents a clear and compelling case for placing people at the center of a renewed commitment to caring for the planet.
“We are faced not with two separate crises, one environmental and the other social, but rather with one complex crisis which is both social and environmental. Strategies for a solution demand an integrated approach to combating poverty, restoring dignity to the excluded, and at the same time protecting nature.” 
Pope Leo XIII wrote the encyclical Rerum Novarum as the industrial revolution and political change swept across Europe. The relationship between employers and employees was changing dramatically. Individuals had become wealthy, but most remained poor even though they worked hard. Pope Leo XIII's encyclical spoke of the condition of the working classes during a time when many advocated revolution.
Quadragesimo Anno was written by Pope Pius XI in 1931 forty years after Pope Leo XIII's Rerun Novarum on the Condition of Workers. He wrote this encyclical to address the ethical challenges facing workers, employers, the Church and the state as a result of end of the industrial revolution and the onset of the Great Depression.
Pope John XXII, 1961
Pope John XXIII wrote this encyclical in 1961 to continue the tradition of Rerum Novarum (1891) and Quadragesimo Anno (1931). The world had changed considerably in the previous 30 years both politically and economically. The Great Depression and World War II had ended, the cold war had begun, and technology allowed for increased productivity, but vast poverty remained across the globe.
Pope John XXIII wrote the encyclical Pacem in Terris in April of 1963 to address a world deeply engaged in the Cold War. The Berlin Wall had just gone up and the Cuban Missile Crisis frightened millions as nuclear weapons began to proliferate.
At a time in world history marked by powerful new weapons, rivalry, and fear His Holiness sought to reassure not only the Catholic World, but also all people, that peace on earth is possible through the divinely established order.
Gaudium et Spes was issued when the Second Vatican Council ended in 1965. The document summarizes the council and gives an outline of the Church’s social teachings in a changing world.
The world has seen enormous development and progress that has amazed humanity, he says, but it has also caused many to worry about the social implications of a quickly changing society as advances in technology and power threaten people. Never before has there been so much wealth simultaneous with so much hunger and poverty.
Pope Paul VI wrote the encyclical Populorum Progressio in 1967 to address the world economy and its effect on peoples around the world. At this time many nations saw their economic development stall, while others continued to grow at a record pace. In the document he talks about the rights of workers to a just wage, job security, reasonable working conditions, and to join a worker's association.