Zusak took a big chance when he chose the narrator and voice for his novel. The narrator is Death, and it turns out that Death has a heart and even a sense of humor. Dark humor, indeed, but humor. Death is also sentimental.
The story is about Liesel Meminger, a German girl age nine in the year 1939 when she's taken by her mother to live with foster parents. Her brother dies on the way, and we expect that her mother doesn't survive much longer. Liesel's foster parents are Rosa and Hans Hubermann, and they live in the town of Molching, near Munich. We get to know them and some of the other residents of the town well. If you think there are going to be terrible events and plenty of suffering, well, you're right. But there are happiness and music and love, too.
Leisel is the book thief of the title, and the first volume she steals is The Gravedigger's Handbook. Hans teaches her to read from this book, and she steals others over the years. Eventually she writes her own book, and the writing saves her life. It doesn't save anyone else, however. (This isn't a spoiler. Death doesn't believe in suspense, and lots of plot points are revealed long before they happen.)
This is the kind of book I hesitate to recommend because I'm sure it's not for everybody. I liked it a lot, myself. You could always take a look and see what you think.