What does the act of book thievery teach Liesel about life and death?

All the books have meanings. The Gravedigger's Handbook, for example, was stolen from the graveyard her little brother was buried in.

Also Hitler's Mein Kampf acts as a shield for Max to create his own book. Stealing books hence become a sense of liberation and inspiration, not only for the books but the people who use them as well.

thanks. Is Hitlers's Mein Kampf the book obtained by Liesel at the book burning?

No, the Nazis would never burn Mein Kampf. I think Max just had it himself.

Max did not just obtain Mein Kampf. Hans sent the book to him with a key taped to the cover allowing him to unlock the door of 33 Himmel Street.