In Robert Heinlein's I WILL FEAR NO EVIL, the very old, fabulously rich protagonist arranges to have his brain transplanted into a young body, healthy aside from brain death (the result of a mugging). Rather than a "brain transplant," this operation should more accurately be called a "body transplant," since identity resides in the brain. An Italian surgeon makes the far-fetched claim that a "full body transplant" will become possible in about two years:Full Body Transplant
Oddly, however, he envisions attaching a severed head to the donor body rather than transferring a brain from one skull into the other. The project evokes images of vintage mad scientist movies. I'd think if the process could be accomplished at all, it would be easier to implant a brain than an entire head with esophagus, windpipe, etc., as well as nerves and spinal connections, plus the challenge of keeping eyes and ears functional.
More cautious scientists point out the unlikelihood of making those neural and spinal connections viable in the near future, given that we still don't know how to restore function to a person paralyzed by accidental damage to the spine. And the inevitable question of "ethics" comes up. In principle, I don't see why a body transplant would be any less ethical than the reuse of a single organ or a group of organs (e.g., a heart-lung transplant). People have been willing their bodies to medical schools for teaching and research for a long time. What's the essential difference between that kind of donation and using a donated cadaver to house a transplanted brain?
In I WILL FEAR NO EVIL, when Johann Smith wakes up in the body of his young secretary, Eunice, he finds Eunice's spirit lingering in her flesh, and they have lively mental conversations throughout the novel. The prospect that some spark of the original inhabitant might remain in a dead-and-revived body lies, so far, outside the realm of science as we know it.
What about transferring a live brain into an artificial body? In the present state of medical science, I suspect the possibility of creating such cyborgs would be further in the distant future than a viable brain-body transplant.
Margaret L. CarterCarter's Crypt