Best books for dealing with bereavement (loss of a parent) please

[bluehairnewhair]

Looking for books aimed at adults.

Any you personally recommend, that helped you in the grieving process?

Many thanks.

Sad by Michael Rossen? Some say its aimed at children but it says very simply what I feel but am most of the time am unable to articulate. I know of other grieving adults who say the same thing.
For me this sums up how I feel not so much the people wont like me but the pretending to be happy when realIy I'm sad.