A Brief History of Time by Stephen Hawking
A Brief History of Time attempts to explain a range of subjects in cosmology, including the Big Bang, black holes, light cones and superstring theory, to the nonspecialist reader. Its main goal is to give an overview of the subject but, unusual for a popular science book, it also attempts to explain some complex mathematics (wikipedia). Although Hawking was never able to prove/disprove time travel, his books are a must read for anyone with an interest in space and time.
a great read while you're traveling through a wormhole.
$14.95 paperback