Science Fiction and Fact
1934
"Sidewise in Time"
While physicists contemplate waveform collapse, author William
Fitzgerald Jenkins writes of parallel worlds under the pen name
Murray Leinster. In the story "Sidewise in Time," a mathematics
professor named Minott predicts that patches of parallel
universes—worlds where human history unfolded
differently—will start to tear through into our reality. When
that actually happens, Minott leads a band of students on an
adventure across the parallel worlds, hoping to locate and rule a
world that lacks sophisticated technology. "Sidewise in Time" isn't
the first story to feature parallel worlds, but it does bring the
concept to a pulp science fiction audience when the story is
published in Astounding Stories in 1934.