"Elsewhen" (1941) is a science fiction novella by American writer Robert A. Heinlein, concerning time travel and parallel universes. It was first published as "Elsewhere" in the September 1941 issue of Astounding Science Fiction, under the pen name Caleb Saunders, and was reprinted in the 1953 book Assignment in Eternity, with some minor changes, and an additional character and that character's journey. Story The story concerns five (originally 4) diverse students who attend a philosophy seminar. The professor, Arthur Frost, explains that he learned how to use his mind to go back in time and correct a bad mistake in his life. Using hypnosis he lets them travel to alternate worlds of their choice. All the students disappear except one, Howard Jenkins. The hypnotic suggestions had no effect on him, because he could not at all believe that it was possible. He is distraught at the disappearances, but the professor assures him that they all received a hypnotic suggestion to come back in two hours. After two hours the students start coming back, and they tell their stories. In each case, the subjective time elapsed was much longer than two hours. Some of them spent a whole lifetime in the alternate world. The first one back is Martha Ross. She comes back as an angel. She lived as a missionary in the parallel world, died for her cause, and went to heaven. After telling her story, she disappears. (This section was not part of the original story.) Next arrives Helen Fisher. She has traveled multiple, very improbable timelines. One of them was in prehistory, where she lived with an old Neanderthal. He was treating her fatherly, and she enjoyed the place, until she was assaulted by a young Neanderthal. Another timeline was in modern time New York City, but she entered the timeline backwards. For a short while there she moved backwards in time, until she fainted and got moved into a different timeline. Eventually she arrived in a place with an extra spatial dimension; there she realized she could see inside solid objects. She studied her own body, and performed appendectomy on herself with her nails. After Helen finishes her story, Robert Monroe arrives. He has changed physically, having a shorter, stockier body; with this, and with his peaked hood, he calls to mind a gnome. He is seriously injured: his arm has been badly burned. He perceives his