[karmakurtisaani]

Easily one of my favourite books. My advice for anyone reading it is not to see it as a philosophical book, although some of the philosophical digressions are extremely interesting. Rather, read it as an autobiography of a person suffering from an obsession, and his quest to connect with his son. The end was very satisfying from this point of view.

Edit: so to answer your points

1. No need to.

2. Worth reading the whole thing.

3. At the first reading when younger, one might focus too much on the philosophy and miss the story of the person behind the thoughts. It's not a book where you learn philosophy, but how this person thinks and how it impacts his life. With some life experience and perspective this aspect is much more interesting.