In The Book Thief, what does the act of book thievery teach Liesel about life and death?

I think one of the more interesting aspects about Liesel's
book thievery is the way that it leads to her unlikely friendship with the Mayor's wife,
and how this friendship leads her to discover the intense sadness of grief of the life
of the Mayor's wife and how she in many ways is living as a dead person, though still
alive. Throughout the novel we are given images of death from the people that literally
die to the death of culture as cetain books are burnt. However, the psychological deaths
of people are symbolised in the figure of the Mayor's wife. Note the following
exchange:

The
mayor's wife tightened. "I used to read in here, with my son. But
then..."

Liesel's hand touched the air behind her. She saw
a mother reading on the floor with a young boy pointing at the pictures and the words.
Then she saw a war at the window. "I
know."

The psychological
death that the Mayor's wife has suffered is symbolised in the way that she does not read
any more and she is invariably seen in a bathrobe and slippers. Liesel learns that her
life has stopped, but through their relationship, the Mayor's wife shows that life can
continue as she comes to care for Liesel and takes her in after the bombing that brings
to a close this exciting and novel story.