Cariou v. Prince
Cariou's original (left) and Prince's alteration (right).
Images from the opinion of the court.
The Circuit Court declared 25 of the 30 Prince works to be fair use, and remanded for re-argument on the other 5. However, the case settled after the appeals court's ruling so we'll never know how the court would have ruled on those 5 works.
Richard Prince is still producing appropriation art, and he lately made the news for appropriating images from people's Instagram feeds.
Patrick Cariou has several other photobooks, which you can see and purchase on Amazon.