I'm also annoyed by the book itself. I hauled out my DVDs from Seasons 3 and 4, trying to find a moment where Gale gives Walter an inscribed copy of Leaves of Grass, and I couldn't find one; maybe I overlooked it, and if so, I'm sure one of you will point me to the episode with exact timecode, because y'all are absolutely on-point that way, but this seems like a ret-con job to me. We saw Walt take a copy of Leaves of Grass out of a box at the start of this season, but I don't believe we ever saw Gale actually give him that particular book with that particular inscription, did we?