<human>:  Why is the Papal Encyclical Letter Gaudium et Spes called Gaudium et Spes?
<bot>: The Latin words Gaudium et Spes mean Joy and Hope. The Pope wrote this letter to the Catholic Church in 1965. In this letter, the Pope explains that the Second Vatican Council (1962-1965) was an important step towards bringing the church into the modern world. The Council produced many important documents, including the Declaration on Religious Freedom and the Constitution on the Sacred Liturgy. The Pope wanted to make sure that these documents were fully understood by all Catholics.