I haven't read a ton of Stephen King books, since I'm not that into heart-pounders, but this one—11/22/63—was awesome.
High school English teacher Jake Epping, by way of his friend Al who owns the local diner in Lisbon Falls, Maine, discovers a portal into the past that lets him step back into the era of sock hops and 10-cent root beer.
But there are a few rules. Every time you step through the portal and change something in the past, the next time you return you automatically reset all the original shifts you made. And whenever you return to the present, no matter the length of time you spent in the past, only 2 minutes have gone by in present day.
Al's dying wish is for Jake to return to that era to successfully prevent the JFK assassination on 11/22/63, something Al attempted himself but could not achieve. When Jake accepts, it turns out, inevitably, to be an even more fraught task than he thought he was in store for.
It's fascinating to meet Lee Harvey Oswald, and even Jackie and John Kennedy, through Jake's eyes, and experience the nuances of America in the early 60s. The book also somehow managed, for me at least, to avoid making time travel a cliche, even in its exploration of the downsides of trying to change the past. I totally get why Hulu produced an eight-part series (produced by Stephen King and J.J. Abrams) from the book, starring James Franco.