The Four Million

"The Four Million" is the second published collection of short stories by O. Henry originally released in 1906. There are twenty-five stories of various lengths including several of his best known works such as "The Gift of the Magi" and "The Cop and the Anthem".
The book's title refers to the then population of New York City where many of the stories are set. 

William Sydney Porter (September 11, 1862 – June 5, 1910), better known by his pen name O. Henry, was an American short story writer. His stories are known for their surprise endings.