found this on another forum. thoughts?
I think the book came from Gretchin Black (her maiden name). Hmm, Gretchin Black, Walter White and in between them, Gray Matter, hmm.
http://i.imgur.com/LLRqS.jpg
Ep 306, Walt meets Gale, Gale talks about a Whitman poem, Walt goes home and reads it in his book! He already had the book it seems.
It fits with the general story telling this show has employed. There have been numerous coincidences that if they didn't occur would have made the story fall apart.
Crazy 8 escapes the basement only to run into Walt driving home, Walt running into Jane's dad at the bar(edit; actually this one might not have affected story much), Walt over hearing that the lawyer is about to flip.
I'm sure there are more coincidences, now, Hank puts the pieces together based on the incorrect assumption that GB is Gale.
And it takes away the "Walt leaves a book from Gale lying around where anyone could find it" sloppiness out of the equation.