11/22/63 by Stephen King
When Al finds a portal to 1958 in his diner, he talks Jake Epping, a local English teacher, into going on a mission back in time to stop the assassination of JFK from happening. But they find you really can't change the past without drastically changing the future.
I'm not usually a reader of Stephen King novels, mostly because he creeps me out. But I actually really enjoyed this book. I loved how King made references throughout to some of his other books (IT, Shawshank Redemption, The Body, etc.) and how I really didn't know what was going to happen next. It was also interesting to know that King spent over a decade researching the JFK assassination for this book. 11/22/63 is a little long, but well worth the 700 pages or so.
I give it a B+.