I read this 10–20 years ago. It's a hard sci-fi book about a man — a physicist — who invents something that swaps spheres of matter with somewhere else. I think the swap was between universes, but it might have been between different times.

He increases the power of the device at some point and swaps a sphere containing himself; I think he ends up inside a tree. He also goes outside of the tree (on a different trip) — into an unfamiliar countryside. There was some kind of timer, I think, to swap him back.

Someone abducts him (I don't remember why, or if it's related to his invention), and he uses the invention to escape; he uses the device to swap part of his abductor's brain with something else, killing him.

I'm pretty sure there was a 1:1 mapping between locations here and the other place, so that when he went there, and he walked within that world, he would be returned to our time/universe to a different location (compared to where he started).

I read it in English, and it's a full length novel.

  • My first impulse was Ernest Clines's The Fold, but rereading desriptions, that does not match up.
    – FuzzyBoots
    Commented May 17, 2020 at 16:00
  • 5
    Possibly "Twistor" by James G. Kramer? See the top (unaccepted) answer at scifi.stackexchange.com/questions/176164/… for more details.
    – Otis
    Commented May 17, 2020 at 17:21
  • Sounds sort of (but not exactly) like Asimov's The Gods Themselves. Commented May 17, 2020 at 19:30
  • 1
    @Otis Yes! That's the one. Add it as an answer so I can accept it? Commented May 17, 2020 at 20:39

1 Answer 1


As noted by Otis and agreed by the OP, this appears to be Twistor (1989) by John G. Cramer. (Note that the author's name in the previous answer is incorrect.)

The book has had a number of different cover designs; you can view them on ISFDb.

One of the better synopses reads:

David Harrison, a young physicist at the University of Washington, accidentally discovers the "twistor" effect," which opens a gateway to alternate universes. Threatened by thugs hired by corporate spies who want to exploit his discovery, David, along with two young children of one of his colleagues, jumps into another world. Once there, he must use his wits and scientific skills, like a modern Robinson Crusoe, to save the children and himself and to get home.

The author's own website has this:

A condensed-matter physics experiment in a university physics laboratory produces an unexpected breakthrough, when the apparatus begins swapping normal matter with “shadow matter.” Industrial espionage goes awry and young physicist David Harrison and two small children find themselves inside a giant tree in an alternate Earth populated by strange, wonderful, and dangerous six-legged wildlife. David and the children must find a way back, while dealing with the local fauna and peeking and poking at the Earth they left to thwart the agents who caused their problems.

The previous answer may have a few more details.

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