The Phantom of the Poles is a speculative science book written by William Reed and first published in 1906. It presents an unusual and now-debunked theory: that the Earth is hollow and contains large openings at both the North and South Poles.

William Reed (1830-1920) was an American author best known for his 1906 book The Phantom of the Poles, in which he advocated the Hollow Earth theory - the idea that the Earth is hollow and accessible through openings at the North and South Poles.