Ten Days in a Mad-House is a book by newspaper reporter Nellie Bly. It was initially published as a series of articles for the New York World. Bly later compiled the articles into a book, which was published by Ian L. Munro in New York City in 1887. The book comprised Bly's reportage for the New York World while on an undercover assignment in which she feigned insanity at a women's boarding house, so as to be involuntarily committed to an insane asylum. She then investigated the reports of brutality and neglect at the Women's Lunatic Asylum on Blackwell's Island.
The book's graphic depiction of conditions at the asylum caused a sensation which brought Bly lasting fame and prompted a grand jury to launch its own investigation with Bly assisting. The jury's report resulted in an $850,000 increase in the budget of the Department of Public Charities and Corrections.