Twilight- The apple represents the 'Forbidden Fruit' which the hand holding the apple is offering the person if he/she will eat it or not and as we all know the Forbidden Fruit is dangerous. Its like Edward is the apple and asks if Bella wants Edward or not and if she accepts, there will be consequences in accepting Edward.

New Moon- I dont know because Stephenie wasnt involved in making the cover. I do know thought that the New Moon is the darkest side of Bella's life.

Eclipse- The ribbon is ripped, and the longer part of the ribbon is Edward and the short side of the ribbon is Jacob. I think =P

Breaking Dawn- The red pawn is the weaker human Bella and the Queen is the stronger vampire Bella who leads the Cullens to success.


Well hope that helps :)

hellgirl223 thinks the same as me ;]

but i think eclipse could have 2 meanings,
1, Bella being torn in half deciding between Edward and Jacob
2, Bella is struggling to break off from her human life and become a vampire..... or something like that ;]

SMeyer explains about the cover meanings on her website ;)