One hundred and five years ago, in April 1919, Mani Ram, a middle-aged dental surgeon, frantically ran to one of his son’s favorite play areas. His son, Madan Mohan, enjoyed playing at Jallianwalla Bagh, an empty plot of land in the center of Amritsar, Punjab, but had not come home. Mani Ram was worried because British officer General Reginald Dyer had just ordered his troops to cordon off Jallianwalla Bagh and open fire on all Indian subjects without warning. His officers fired 1,650 bullets at Indians...