"In the Garden of Beasts" by Erik Larson (he also wrote "Devil in the White City") The inner flap refers to his writing as "narrative non-fiction". It's non-fiction, but I think it's written in a way that makes one want to keep reading.

My mom read "The Help" for her book club, and she really liked it -- I asked her to let me read it before she returned it to the library. But my dad took it back, so now I'm on a waiting list for it.