Until 1946 she was a Roman Catholic teaching nun in India, devout, dynamic, but apparently otherwise unexceptional. Then, on a train ride to Darjeeling, she felt the touch of a divine command. Its message: she must quit her cloistered existence and plunge into Calcutta's clamorous slums to care for "the poorest of the poor."
She did just that, leaving the genteel girls' school where she had been teaching to create a new order among the poor of India's most desolate city.
The Missionaries of Charity have since grown into a worldwide order numbering more than 1,800 nuns, 250 brothers and thousands of...