The Reader by Bernard Schlink.
The book begins with the story of fifteen year old Michael Berg and Hanna who is twice his age. Michael meets Hannah as he falls ill on the way home from school and Hanna comes to his aid. Michael returns to thank her and then is seduced by Hanna and they become lovers. Michael is asked to read aloud to Hanna and he spends time reading to her daily.
I began to think that their infatuation for one another was the main focus of the story. However, Hanna then completely disappears from Michael's life and the next time he sees her is when he is a law student and Hanna is on trial for the crimes she has committed as a prison guard.
Hanna tries to defend herself but does so badly and then Micheal realises Hanna's secret that she finds more shameful than her war crimes in Nazi Germany. After the trial Michael carries the knowledge of Hanna's secret with him until he realises he needs to put the past behind him.
The book brings up numerous themes guilt, shame, secrets and betrayal