O. Henry was the pen name of William Sydney Porter (1862-1910), who wrote some of the most famous and beloved stories in English. They are so famous for having surprise endings that another name for a surprise ending is an "O. Henry ending." Nevertheless, his stories are beautifully constructed and are enjoyable to read even when the ending is known.
Many of his stories are set in New York, a city which he sometimes called "Baghdad-on-the-Hudson." Many of them concern ordinary people of limited means. One of his story collections is entitled The Four Million, which was both the population of New York at that time, meaning that he was interested in everyone, and not just "The Four Hundred," the cream of high society.
Undoubtedly his most famous story is "The Gift of the Magi," about an impoverished couple who make personal sacrifices to show each other their love at Christmas time. Like Charles Dickens' A Christmas Carol, it is often read aloud during the Christmas season.
But he found stories everywhere. One of his most famous stories, "A Municipal Report," opens by quoting Frank Norris: "Fancy a novel about Chicago or Buffalo, let us say, or Nashville, Tennessee! There are just three big cities in the United States that are 'story cities'; New York, of course, New Orleans, and, best of the lot, San Francisco." Thumbing his nose at Norris, O. Henry sets the story in Nashville.
"The Random of Red Chief" is an hysterically funny story about the kidnapping of a bratty, obnoxious boy of ten.
"A Retrieved Reformation" concerns a moral crisis in the life of a safecracker who decides to go straight, and is faced with the decision of whether to reveal himself as a safecracker in order to rescue a child locked in an airtight bank vault.
"The Last Leaf" is a heartrending tearjerker about a young woman in danger of dying from pneumonia. She has been staring through a window, depressed, watching the winter wind blow the leaves from an ivy plant on the brick wall opposite. She is convinced she will die when the last leaf is gone. An artist finds a way to save her life.