How is each of Liesel’s book titles an ironic comment on the times? What is ironic about the title of Max vandenburg’s book?

Liesel doesn’t begin to learn how to read until she is ten yet she becomes such a prolific reader and writer. She begins to read in the Chapter "The woman With the Iron Fist."

It's ironic that Death narrates a story about the Holocaust

In 1936 Jesse Owens, a black American athlete, wins four gold medals at the Olympics in Berlin. This infuriates Hitler who had his "master race" athletes competing. Alex Steiner, a card carrying Nazi boy, paints himself black and runs the 100 meters to emulate a black athlete. Chapter "The Jesse Owens Incident"

Liesel is taunted by her classmate Ludwig Schmeikl. Rudy urges her to ignore Ludwig, but she instead savagely beats him. Still enraged, she also punches Tommy a few times, Remember Liesel is a girl! Chapter THE HEAVYWEIGHT CHAMPION OF THE SCHOOL-YARD

Max uses Hitler's book to write his text in. That was pretty ironic.