Page to screen vs screen to page

Yesterday I watched the film 'Blood Father' the film adaptation of the book by Peter Craig. I was not only enticed by the trailer but also by the fact that I hadn't seen a Mel Gibson film since 'How I spent my summer vacation' a couple of years ago. A film by the way which reminded me of how much I enjoyed Gibson's screen presence.

Needless to say I enjoyed the 'Blood Father' immensely and when the credits began to roll I was reminded that the story originated from the novel of the same name. And it got me thinking, there is always much talk of how adaptations differ from books (in most cases people will often read the book before watching the film).
But how many of you convert backwards and does it change your perception of which is better? Would you agree that without film adaptations would many of us find out about authors who are now household names?
After all were it not for the American Psycho motion picture I probably wouldn't have begun to read many of Bret Easton Ellis's works and were it not for the Shining or various other Stephen King adaptations I probably wouldn't have read any Stephen King either, and both are now two of my favourite authors (by the way the book has won every time).

I have already added Blood Father to my to read list but was curious as to how many of you have been lead from screen to book and if so which films and authors have you discovered?