The passage chiefly concerns ....... .

The 20th century began quietly for the United States, but soon new forces brought profound
changes. Although science and technology enriched material life, two world wars and the
prospect of a third raised grave concern about the future. The federal government intervened
increasingly in the activities of the people. The nation also learnt that it was involved in the
problems of peoples around the globe. Literature reflected the various reactions to the new
circumstances. Some writers were deeply pessimistic; others viewed the same realities with
hope for the future. One literary school surveyed the American past in an attempt to find
meaning for the present. The writing that seemed most likely to survive emphasised enduring
human values and the unquenchable vitality of the human spirit.