Guardini argues that the modern world, which he defines as the period from the Renaissance to the mid-20th century, is coming to an end. He contends that this era, characterized by a focus on human autonomy, reason, and scientific progress, has reached a critical juncture.

He realized that the horrors of the 20th century were not accidental detours from modern progress. Instead, they were the logical conclusions of modern philosophy. The End of the Modern World serves as an obituary for the optimistic assumptions born during the Renaissance and the Enlightenment. 2. The Three Great Epochs of Human History

Guardini’s vision of the future is stark but not hopeless. He predicts a world that is increasingly "non-human" in its structures—where life is dictated by efficiency and bureaucracy rather than organic community. In this new era, the "comfortable" Christianity of the past will vanish.

Guardini's work spans multiple disciplines, including theology, philosophy, and literature. His writings on Kierkegaard, Dostoevsky, and other thinkers have been widely acclaimed, and his own books, such as The Lord and The Church and the Sacraments , are considered classics of modern Catholic thought.