What do the covers of the Twilight series signify? (Why the apple, flower, ribbon, chess pieces?)

The Twilight apple represents several things associated
with divinity:

Knowledge of good and
evil

Knowledge of the mechanics of life and the
universe

Immortality (particularly immortality gained by
feeding on lesser
beings)

Ascension

Sex and
death

Many Yahoo! answers have already been given to the
question of the apple on the cover of Twilight, but there are some possible versions of
the answer that I haven't seen mentioned. There are two trees in the garden of Eden
whose fruit is forbidden and could be symbolized by an apple, although the actual fruit
in Genesis isn't specified. These trees include the tree of knowledge of good and evil
and the tree of immortal life. After Adam and Eve become more like God by eating from
the first tree, they are cast out of the garden because they might eat from the second.
The process of becoming a vampire is associated not only with becoming more aware of
questions of good and evil, but also with trying to become immortal. However, in
Twilight there's a rebellion of two sorts because becoming a vampire means first taking
the serpent's (devil's) advice to eat the fruit, then (in the case of Edward and other
"vegetarian" vampires) trying not to sustain immortal life by feeding on people. Being a
"vegetarian" vampire would seem like something forbidden to most vampires. Therefore,
eating fruit can be considered forbidden both by the Biblical God and by the devil and
traditional vampires.

The apple is also associated with
scientific and carnal knowledge and discovery, particularly in areas which have clashed
with religious faith. Bella and Edward meet while studying cell reproduction in Biology,
one of the subjects most concerned with evolution and forbidden by churches. In the
Twilight novel, Bella drops her books (repositories of knowledge) and Edward picks them
up; in the movie, she drops an apple instead of books. Dropping something, or letting
something fall, is a means of flirting (for instance, at some times in history, a woman
might have dropped a handkerchief for a man to pick up). Bella, in that sense, can't
help flirting, or acting as if she's flirting, because she's so clumsy. Neither Bella
nor Edward can resist "falling" for each other. In the Bible, the fall of Adam and Eve
is followed by Adam and Eve "knowing" each other, that is, having
sex.

Bella is both mysterious and dangerous to Edward
because she's his favorite intoxicant. She's food to him because he's a vampire, but may
be considered poisonous to him, like Snow White's apple (the drug and Snow White
references are both made by Stephenie Meyer, the first in the novel and the second in
her discussion of the apple on her question and answer page). Bella is also the only
human whose thoughts are forbidden knowledge to Edward in any significant way, since he
reads everyone else's.

I have more to add in another
post.

Ivan Dorin