The Science Fiction Hall of Fame, Volume Two is an English language science fiction two-volume anthology edited by Ben Bova and published in the U.S. by Doubleday in 1973, distinguished as volumes "Two A" and "Two B". In the U.K. they were published by Gollancz as Volume Two (1973) and Volume Three (1974). The original U.S. subtitle was The Greatest Science Fiction Novellas of All Time.

The Time Machine is a post-apocalyptic science fiction novella by H. G. Wells, published in 1895. The work is generally credited with the popularization of the concept of time travel by using a vehicle or device to travel purposely and selectively forward or backward through time. The term "time machine", coined by Wells, is now almost universally used to refer to such a vehicle or device.