William Henry Vanderbilt was an American businessman and philanthropist who inherited and vastly expanded the railroad empire built by his father, Cornelius Vanderbilt. Initially underestimated by his father, he proved to be a brilliant financial strategist, more than doubling the family's immense fortune during his tenure. He consolidated the family's control over major railway lines, including the New York Central Railroad, becoming one of the wealthiest men in the world. Despite his reputation for ruthless business practices, he was also a significant philanthropist, contributing to institutions like Vanderbilt University and the Metropolitan Opera.