I will read any book about time travel. This one is good but also a little all over the place. There’s a lot of “Let me explain the SCIENCE to you” parts which were less interesting to me than the human drama, but that part was a bit trauma-filled. The basic conceit: you can only sort of time travel, consciousness only, and only for about 90 seconds, and only into the past. Or... are the supposedly immutable roles in this universe more malleable than that? One of those books where I had to Google the ending because I wasn’t totally sure what happened, a book that rewards close reading.