Mamoon Akhtar was a lowly librarian in the slums of Calcutta. But he had a dream: to build a new school for neglected street children. He founded a nonprofit, Samaritan Help Mission, and began using his own meager funds to build a one-room schoolhouse. He ran out of money before he could finish installing the floor and windows. A reporter for Asian Age heard about him, and wrote a story.  
The entrepreneur and philanthropist Ramesh Kacholia read the story and got in touch with the librarian, who said he needed Rs. 7,000 to finish the...