I have known the author of this book through other works, e.g. his television series in Germany. His stories have always been good but this is the best work of his life. An occupant of the Warsaw ghetto tries to help his fellow Jews sustain life by telling them lies about the Russians being almost there to liberate them. The way this ordinary guy who has just as much to lose as everyone else is motivating people in their most desperate moments is so captivating.
Anyway, the book is really great, the attempt of the author to describe the people's very soul in times of challenge is unique and he does a superb job with this. There is a movie which I haven't seen but it's supposed to be good, as well.
They have made this into a movie with Robbin Williams as Jacob but I haven't seen it.