i love Planet of the Apes but the book is very very different from the novel. not sure i'd consider it a good adaption. great film though.
I think that raises the question of how one defines "good adaptation." Does it mean an accurate/faithful adaptation? I don't believe so. Because the definition of the word "adapt" is "change to fit new circumstances." So to me, a good adaptation isn't one that copies the original as closely as possible. That's more atavism than adaptation. A good adaptation is one that changes the source work in a good way. By that standard, PotA is a very good adaptation. It changed the story in a way that resulted in a classic that transcended its source material.