Probably the most famous exception to this is when the Hangover II movie was sued by Mike Tyson’s tattoo artist who claimed copyright over the lookalike tattoo featured in the film. The parties eventually settled out of court in an undisclosed agreement so precedent hasn’t been set.
I can only imagine that made it to the point of a settlement because there aren’t many high-end lawyers with tattoos. If there had been, one of them would have piped up and said, “Dude, that ain’t exactly the Nike swoosh or the BMW logo. That’s the most generic piece of tribal flash, like ever. We can’t win.” 
On a more serious note, this reminds me a bit of what I deal with in the medical field: patients have a right to their own medical information, but my clinic owns the actual physical folder full of papers. Patients who request their “file” are entitled to receive a copy of it in the format of their choice, but the original stays with us no matter what.
It doesn’t matter if it’s generic looking, it was quite clearly a copy of Mike Tyson’s tattoo as is made explicit in the film (the actual Mike Tyson appears in the film). The only reason the studio settled is because the Judge explicitly made the statement that the suit had “a strong likelihood of success in his claim.”
Thanks for everyone’s comments.
Oh, completely. This is a hypothetical. Not very interesting if the author wasn’t an idiot and made a backup copy, is it? 
This is a great analogy.
I didn’t figure the author had any right to the file on the friend’s computer, but I guess I wondered if there was any way to force Miles to hand over the file. Obviously in this scenario, the only choices would be to sue and/or offer money to get the file back. If there was a lawsuit though, I’m not sure what basis it could have.
Well, Herman Melville comes to mind. I’m pretty sure he didn’t have a backup copy of Moby Dick.
As others have noted, the intellectual property on the file belongs to the author. The computer still belongs to the owner.
No one has mentioned the concept of promissory estoppel. Generally, a promise like “sure, you can use my computer to write your book” is unenforceable unless there is a contract between the parties, which generally requires that both parties create enforceable obligations. So, if the offer was “you can use my computer to write your book if you pay me $1 per day” and you agree, you have a contract. The $1 per day is called consideration. Both parties know what they are supposed to do and each party is entitled to enforce the agreement. Your friend gets $1 per day and you get the computer. Generally, contracts without consideration from both sides are unenforceable.
But promissory estoppel is a common law concept that makes some agreements without consideration, that is some promises, enforceable just like contracts. Promissory estoppel generally applies when fairness requires it. In order to assert promissory estoppel, you must show that: (1) someone made you a promise, (2) he should have reasonably expected you to rely on the promise, (3) you did rely on the promise, and (4) you relied on the promise to your detriment.
In this case, you might have a good claim under promissory estoppel. Your friend promised to lend you the computer. He should have reasonably expected you to rely on the computer because he knows you don’t have a computer and because it is better than writing a book in the looseleaf notebook you would have used otherwise, which doesn’t even have spellcheck and could easily get lost or rained on. You did rely on the promise and wrote your book on it. Finally, the reliance on the promise was to your detriment because you otherwise could have written your poorly spelled manuscript on your soggy notebook but instead your friend now has control of your book. The equitable solution is likely to make him give you a copy of the file if he still has it. It might even be actionable if your friend intentionally deleted it just to spite you, but that’s a little outside the hypothetical.
In Europe and some other places, there are laws protecting against the destruction of a creator’s work without permission. (Under the label of Moral Rights.) E.g., you can’t destroy someone’s painting or statue despite ownership. Clearly this doesn’t apply to copies of a book and such, but I think it might apply to the original of a manuscript.
For handwritten, typed originals, that should be clear. But for computer originals … hmm. Just doing a defrag on a computer HD might “destroy” the original and produce a copy on another location of the drive.
(Note, Moral Rights are part of the Berne Convention, which the US had signed but is only partially part of US Copyright Law. Yet another difference between the US and Europe in this area.)
Do these laws differentiate between willful, negligent, or accidental destruction?