The Crossroads of Time
Everything gets a second chance! That's the shattering discovery Blake Walker made when he learned that there are innumerable parallel worlds - on each of which history has taken a different alternate path!
The Crossroads of Time is a brilliant science fiction novel of how Blake crossed from Alternate Earth to Alternate Earth in a search for the means to save his own home world from disaster.
Andre Norton
Andre Alice Norton (1912-2005) was an American science fiction and fantasy author (with some works of historical fiction and contemporary fiction) under the noms de plume Andre Norton, Andrew North and Allen Weston. Norton published her first novel in 1934, and was the first woman to receive the Gandalf Grand Master Award from the World Science Fiction Society in 1977, and won the Damon Knight Memorial Grand Master Award from the Science Fiction and Fantasy Writers of America (SFWA) association in 1983.
Crosstime
Crosstime is also known as Blake Walker.
Crosstime consists of two primary books, and includes one additional book that complement the series but is not considered mandatory reads. The current recommended reading order for the series is provided below.