I haven't seen this movie but have known about the title for years. Apparently this movie isn't based on a book but I remember hearing about, although not reading, a book with the same(or similar) title in high school as far back as 2001 or even earlier.
shareSince you mentioned it, I searched for it and found nothing. This is in part based on a Short Film by Cam Archer, which was expanded into "Wild Tiger I Have Know". Cam Archer is the Writer, Producer, and Director. Though others like Gus Van Sant had faith in his vision and helped him with the film.
There may be a book with a somewhat similar Title, but I don't think it will be the same Story.