What are the themes of Extremely Loud and Incredibly Close by Jonathan Safran Foer?

The story Extremely Loud and Incredibly
Close has several themes.

The story is primarily
about Oskar who loses his father in the Twin Towers' bombing.  The themes of
death and loss are quite obvious with Oskar,
as is emotional trauma, which his father conveys on the five phone
messages he leaves before he dies (which only Oskar knows about and has heard), and the
trauma Oskar experiences in the loss of his father.

These
three themes are also present with Oskar's grandfather.  Before marrying Oskar's
grandmother, he had been in love with his wife's sister. In Germany, during World War
II, a bombing takes the lives of a number of people (Oskar's grandfather's family and
Oskar's grandmother's family, including the woman Oskar's grandfather loves), but
Oskar's grandmother survives, and Oskar's grandfather eventually marries her.  However,
when he finds that his wife is pregnant, he leaves: he cannot deal with any more loss so
he tries to love no one and remain emotionally distant (though he never quite succeeds
in severing the ties that bind him to others).

Mr. A.R.
Black has experienced loss from the death of his wife, and William Black's father has
died.

Many of the people in this story are dealing with
death and loss; the story describes the different ways in which each deals with this
loss.