Letter to a Christian Nation is a 2006 book by Sam Harris, written in response to feedback he received following the publication of his first book The End of Faith. The book is written in the form of an open letter to a Christian in the United States. Harris states that his aim is "to demolish the intellectual and moral pretensions of Christianity in its most committed forms." In October it entered the New York Times Best Seller list at number seven.

Samuel Benjamin Harris is an American philosopher, neuroscientist, author, and podcast host. His work touches on a range of topics, including rationality, religion, ethics, free will, neuroscience, meditation, psychedelics, philosophy of mind, politics, terrorism, and artificial intelligence. Harris came to prominence for his criticism of religion, and is known as one of the "Four Horsemen" of New Atheism, along with Richard Dawkins, Christopher Hitchens, and Daniel Dennett.