David Brin's Kiln People was published by Tom Doherty Associates in 2002. It's a long book, nearly 600 pages. I got it for Christmas, for which I am grateful. The central premise is that there is a method which allows a person's consciousness, personality, or soul to be implanted into a temporary body (more than one at a time, in fact). The original person remains alive and independent, and the experiences of the temporary can be integrated into the memory and experience of the original. This doesn't have to happen--the original may choose not to absorb the memories, or the temporary body may suffer an accident, and not return before degrading. One unique aspect of the story is that the central character is in more than one story line at the same time, as the original and copies of himself. Even though the book is fiction, it is difficult to read it without examining some important and fundamental issues. What is a human being? Should techniques to accomplish such things be developed, or prohibited? Would it be ethical to produce a temporary body solely for the purpose of trying risky things, experiments, or for thrills? For use in combat?
The plot involves the possibility of a sort of immortality, if a copy can produce a new copy.
The book is full of various wordplays on xerox and ditto, such as "ditective" for a temporay agent produced by a sleuth.
The Kiln part of the title is because the temporary bodies are, sort of, baked from clay in a kiln. They decay after 24 hours or so, into slurry, which can be used in making new temporary bodies. The tycoon who owns the dittoing process is named Kaolin.
Here are some quotes:
What happens to the soul of a ditto who loses his salvation--who never gets to inload back into the "real" self who made him? . . . For that matter, what happens when your original dies? Some religions think there's a final transfer, loading your entire lifestream into God, in much the same way your golems pour their memories back into you at the end of each day. But despite fervent yearnings--and well-funded private research--no one's ever found proof of such transfer to some higher-level archetype being. (pp. 108-109.)
There is a ditto religion. A "preacher" of that religion, himself a ditto, hence temporary, speculates about the possibility of some part of a ditto being united with God. "Does heaven have a place for us, as well? If it doesn't, well, maybe it ought to." (p. 102)
Watching "cut-rate" copies doing hard manual labor, the protagonist wonders:
Squinting at the scene one way, I glimpsed a science fiction nightmare worse than Fritz Lang's Metropolis--slaves and prols laboring for distant masters before toppling to an early death, preordained and unmourned. Squint another way, and it seemed marvelous! a world of free citizens, extending tiny portions of themselves--easily expendable bits--to take turns doing all the necessary drudgery, so everyone can spend their organic lifetimes playing or studying. Which was true? (p. 326)