This is not the type of book that I would normally read so I went into this with perhaps the wrong mindset. On paper, I can recognise that it is a very interesting concept - travelling back in time and trying to right a historic wrong, in this case, the assassination of JFK, but it just didn't grab me. 
 I can recognise that it was well written, the story moved along at a nice pace despite covering years, but for me, I needed to care a little more about the characters involved to really love it, and for 2/3's of the book, I just didn't. 
 The last third of the book was amazing, engrossing and even though I kinda guessed what would happen, I still was reading it and felt my heart going just wondering how it would all sort itself out. The problem for me was that for a book of this length, it took so long for me to get hooked, that I didn't feel the payoff was worth the effort to get there. Jake/George was a good narrator, but not always a sympathetic one for me, so I don't think that happened because I wanted to care when he fell in love, or know that he was feeling conflicted, or guilt-ridden and I just didn't. 
 As I said though, this book wasn't in my wheelhouse, but it was worth reading. I think if you're more into that genre, that style, it would probably flow a lot easier for you, but it just didn't gel with me.