Stephen King's 11/22/63 is a solid bit of SF, as in speculative fiction. The speculation is what if Kennedy had not been killed on November 22nd 63? Maine schoolteacher Jake Epping sets out to stop Lee Harvey Oswald, this even if he is in 2010. This is basically what 11/22/63 is plot wise.
Jake Epping is correcting some GED essays when he comes across one that really gets to him. He then discovers Al's Diner has a doorway to September 1958. Epping gets access to it and decides to right a wrong. Stuff happens and Jake decides to stop Oswald. To do this he will have to go to 1958 and spend five years in the past until Kennedy goes to Dallas.
In some ways King's speculative fiction is about the late fifties and early sixties and how life was simple back then, or so it would seem to someone fifty years hence. There is a bit, at the beginning, and then a lot, towards the end, of the old time travel “What are the repercussions if I change this particular event?” and King navigates this adroitly.
It takes quite a while for Jake (and the reader) to get to November 22nd 63. Most of it is interesting but this King novel is 822 pages so you better be ready for a long ride.
Post climax the story feels rushed and King sounds like he is trying to tie up loose ends leftover from a time machine device he himself does not quite understand.
Long time King fans will like this one. Casual fans will also enjoy it, the dude sure can tell story, but 11/22/63 is not a Stephen King top 10.
Other Stephen King Reviews
Cell: The Stand meets zombies with cell phones.
The Langoliers DVD: Not a horror movie, a horrible movie.
Doctor Sleep: What happened to Danny Torrance of The Shining? You really want to know.
Revival: Reverend turned preacher and carny dabbles with electricity to discover the unknown.