Replay by Ken Grimwood
Purchased for my Kindle several months ago. I started it a few days ago, and it has been keeping me up late nights. It is very interesting and imaginative. Very well written. I'm about 3/4 of the way through, and I went back to Amazon and ordered a used hard copy so I could lend it out.
Middle-aged man goes in to the office in 1988, has massive heart attack, and dies. He wakes up in his college dorm room in 1963 and has to relive his life. He makes different life choices, marries a different wife, eats healthy and exercises, and even so, in his second go round at 1988 he has another massive heart attack and dies. Again he wakes up in 1963 and starts over.
Part time travel. Part mystery. Part love story. Really enjoying it.