How to Stop Time

I found the book How to Stop Time by Matt Haig when I went in search of a new time travel book. Time travel may be my favorite genre, but also one that I've had a hard time in the last few years finding a new book to sink into. How to Stop Time isn't actually a time travel book but its close. The story revolves around the central character of Tom Hazard. Tom is 41 years old and lives in London. His body looks like a normal 41-year-old but actually, he just ages incredibly slowly (it takes 15 years for him to age 1 human year) so is instead actually over 400 years old.