Train to Pakistan, by Khushwant Singh

Partition of the British Indian empire in 1947 into India and Pakistan is the setting for this tale. Muslim, Sikh and Hindu live peacefully side by side in villages throughout the empire prior to Partition (just as Christians, Jews and Muslims lived peacefully side by side throughout the Middle East for hundreds of years and Americans of diverse faiths and cultures live together peacefully in current day United States). During Partition, this balance is disrupted as people of differing religions are moved to their new countries by the new governments. Millions of people were killed. This is a tale of one such village in Punjab. I think diversity makes a society strong and living among people who are different from you keeps them familiar and less threatening in their "otherness." When we segregate into homogeneous groups and put up walls, people who are different from us become even more unfamiliar. These homogeneous groups lose capacity for open and tolerant thinking; they worry among themselves about things not worrisome and become afraid. Bad things come of this. This is a cautionary tale for Americans (and the French and British, too)  - the rise of populist/nationalist groups and the rhetoric surrounding the election of Trump as President augur things similar. America is better than this.