I am reading a very intriguing book called Eva, by Peter Dickinson. I found it via a booklist that is posted on Robin McKinley's blog. (Peter Dickinson is Robin McKinley's husband.) Robin and her blog readers have all posted to this booklist. WARNING: if you like fantasy, you are liable to find hundreds of books to interest you on this list. You may never dig yourself out of the pile of books-to-be-read...
Anyway, back to the book, which was written in 1988. It is set in the future, when the world is grossly overpopulated, and there are very few animals left. Eva is very badly injured in an automobile accident, and to save her, they implant her consciousness into the body of a chimpanzee.
I haven't gotten very far in the book, but there are a wide variety of themes here: the definition of "self"; ethics of medical experimentation, especially on animals; corporate sponsorship and exploitation (yep, that's how they paid for her treatment); etc. I'm looking forward to finding out how these themes develop.