Sidewise in Time

work by Leinster

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July 16, 2026

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Murray Leinster's Sidewise in Time (1934) is a science fiction work that explores the concept of alternate histories and parallel universes. Instead of focusing on a single past or future, Leinster's idea allows for travel between multiple existing timelines. This concept expands the possibilities of time travel narratives beyond simple paradoxes, opening up a "multiverse" where humanity's universe is just one among many. This theme of alternate realities has become a significant convention in science fiction, offering a vast canvas for storytelling by allowing authors to explore "what if" scenarios and mutate historical events and figures.1

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science fiction
Alternate histories and parallel universes
Murray Leinster’s Sidewise in Time (1934) expanded the possibilities by suggesting a vast multiplicity of “histories,” all occurring at the same “time.” Under the scheme Leister proposed, one need not limit oneself to one past or one future but might travel between many alternate worlds existing in…
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Murray Leinster’s Sidewise in Time (1934) expanded the possibilities by suggesting a vast multiplicity of “histories,” all occurring at the same “time.” Under the scheme Leister proposed, one need not limit oneself to one past or one future but might travel between many alternate worlds existing in…
Read More