[JennyHallu]

My take on the Eagles were that they were to enhance our understanding of Frodo's state of mind. The task is over, and he's reached a point of physical and emotional exhaustion he's managed to stave off all this time. He sees the Eagles through a haze of unreality, he's confused as to what story he's in. We are almost given the impression that the Eagles are a hallucination, and are delighted and surprised when we find Frodo and Sam are still alive at the beginning of the next. They needed a miracle, and they got one.

Perhaps it's a Deus Ex Machina on purpose. As it has been previously defined, an Act of God. That doesn't necessarily imply any weakness on the part of the author, but a story in which God is very real.

As for Coincidence, I fear I must disagree with Jeffrey Archer there. If he is so unreliable most of the time, Essex, he is probably unreliable all of the time. Half of Shakespeare is reliant on coincidence...A Comedy of Errors (an entire genre!) is entirely dependent upon coincidence for plot and resolution.