I have some of that kind of stuff...

But I reckon the prize book I have is A Boot Full of Right Arms by Evan Green. Both of my copies were obtained from charity shops and one of them was autographed by Green and was a review copy for a paper or magazine.

This is a book that you cannot put down, sheer drama pervades as it tells the story of the 1974 London to Munich Rally from the point of view of the crew which led the event as they headed into the Sahara Desert.