The document traces the development of Catholic social teaching over the past 100+ years, from Pope Leo XIII's 1891 encyclical Rerum Novarum addressing the conditions of workers following the Industrial Revolution, to more recent documents addressing issues such as globalization, the environment, and human dignity. It discusses papal letters and teachings covering topics including labor rights, economic systems, poverty, development, and the Church's role in advocating for social justice issues in the modern world.