Most of us always ask ourselves, “what if I had done something different with my life?” The literary genre of Alternate History looks at “what if” scenarios from some of history’s most pivotal turning points and presents a completely different version, sometimes based on science and fact, but often based on conjecture. The exploration of how the world would look today if various changes occurred and what these alternate worlds would be like forms the basis of this vast subject matter.

Since the 1950s, this type of fiction has to a large extent merged with science fictional tropes involving cross-time travel between alternate histories or psychic awareness of the existence of “our” universe by the people in another; or ordinary voyaging up-time (into the past) or downtime (into the future) that results in history splitting into two or more time-lines. Cross-time, time-splitting and alternate history themes have become so closely interwoven that it is impossible to discuss them fully apart from one another.