The main recollection I have is that the main protagonist is an engineered being, mostly human, but who can enter a state that lasts a few weeks, in which the protagonist can change its body, even its sex.

The protagonist can use some means to calculate future events, but the way he does that changes when he changes his body. Sometimes the calculation is more mathematical, others it is more holistic. I also seem to recall the at first he is not exactly a prisoner, but is locked out and eventually escapes.

  • When did you read this book? Do you recall the cover, or the names of any characters or places? Does it take place on a planet (possibly Earth) or is it more space opera? Why does the protagonist change its body? Is it a spy, an assassin, a cultural researcher, a law enforcer...
    – DavidW
    Nov 14, 2023 at 22:21
  • (The most obvious example of a willful polymorph who has realistic limitations and requirements to change is Bora Horza, but he doesn't fit the predict-the-future part.)
    – DavidW
    Nov 14, 2023 at 22:24
  • Doctor Who can do this transformation as part of his/her regeneration. But it's a TV series, not a book.
    – pts
    Nov 15, 2023 at 15:06
  • @DavidW, thanks for the edits, much more clear like this.
    – Ormazd
    Dec 4, 2023 at 15:57

2 Answers 2


This could well be the Transformer series by M A Foster. The Morphodite (1981), Transformer (1983), and Preserver (1985). The main character is a genetrically engineered assassin who has been loosed by his creators but is disinclined to carry out that work. In the first book the main character requires a lot of external calculation to model the network of interacting social systems that describe the present and allow one to identify key points where intervention will drastically change how the near future develops. The main character also has the separate ability to morph into another human shape; each morph regresses his/her age by 10-20 apparent years and involves a gender change. Old man -> middle-age woman -> male youth -> infant girl. The morphing is painful and as I recall only undertaken as a last-ditch escape mechanism. Over the course of the three books it turns out that each morph further internalizes the social calculation ability so that it requires less external calculation and becomes more instinctual. Also the scope of the underlying model extends each time, till by the third book it extends to include off-world actors who were responsible for the original creation of the Morphodite back in book one. Revenge ensues, in the form of a butterfly-effect intervention, where the ramifications on one tiny action taken by the protagonist ripple out to cause the downfall of those off-world actors. enter image description here


I wonder if this is "Consider Phlebas" by Iain M Banks? Some details match, though not all.

The main protagonist is Horza, a Changer, a species that can, well, change their appearance over time.

He starts the book, memorably, literally up to his neck in excrement, facing a novel method of execution by drowning.

  • I discarded this as a possibility already, since Bora Horza has no ability to predict the future. (Anything would have helped; he made some pretty terrible decisions...)
    – DavidW
    Nov 14, 2023 at 22:31
  • 1
    @DavidW I didn't see your comment before I posted CP as an answer. And I nearly didn't bother for the reason you give, but I've seen less likely answers come up positive, so I thought I may as well. However I think Ethan's hit on the correct answer.
    – Moriarty
    Nov 14, 2023 at 23:36
  • That's fair. I forget sometimes how long it can take to chase down (and verify) just a couple of decent links.
    – DavidW
    Nov 14, 2023 at 23:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.