What are some good scientific time travel books?

I'm not talking about fiction, but what are some books that discuss time travel theories?What are some good scientific time travel books?There are none because there are no viable time theories. However some physics texts deal with things which affect time such as traveling at close to the speed of light or in a extreme gravitation field. Under these circumstances time slows down but does not reverse. The only way I know of to travel in time is the way we do every day. Grow older.What are some good scientific time travel books?people who read science fiction believe in time travel. people who read science do not