CLIMAX!
In Eclipse the climax starts about 7/8 into the book. The climax is when the army of newborn vampires comes to Forks, while Edward, Bella, and a young werewolf called Seth are hiding in the mountains so that the army can't find Bella. That is what is leading up to the climax because after the fighting has started Victoria, the vampire who wants to kill Bella, and a young vampire called Riley finds Edward, Bella and Seth. The peak of the whole book is the fight between Edward and Seth against Riley and Victoria. To help the fight Seth pretends to be badly hurt so that Victoria and Riley won't pay any attention to him.
The bad part about that idea is that Bella know thinks that Edward can't fight Riley and Victoria at the same time, so she wants to act like the 3rd Wife. Before she can do that though, Edward and Seth managed to kill Riley and Victoria. The conflicts that lead up to the climax happened in the earlier books in the series when Bella killed Victoria's husband, James. If your interested in finding out more about why Victoria wants to kill Bella so much, I suggest you read the other books in the series.
This is an example of a conflict between a person and a supernatural being, I'm saying this because you don't often come across conlicts like this!