Perhaps it was inevitable that my fondness for novels involving time travel would lead me to this slim but fascinating non-fiction work by physicist, Paul Davies. Despite the provocative title, Davies doesn’t actually give step-by-step instructions for building a time machine in your garage, more’s the pity. But he does explain in plain English why we’re already time travelers (moving toward the future at the stately pace of one second per second) and how the universe just might allow us to do far more—eventually. Want to get to Year 3000 in a hurry? Build a rocket that can attain 99.999999999% of the speed of light and you’ll be there in six months. Want to get back now from then, or visit some other time that relative to now is in the past? You’ll need a wormhole and Davies provides helpful, if daunting instructions for building one. If a traveler from the future ever does show up, don’t be surprised if he’s got a copy of this book in his back pocket. ( )

After reading it, I know why a time machine is not a total fantasy.

I was somewhat disappointed by this slim book. Davies obviously knows what he is talking about, but I felt the book would have been better with more detail (like equations). For disclosure's sake, I am pursuing a PhD in physics, so I might have a skewed idea for the appropriate level of detail.

The other problem I had with this book is that, since it covers a practical (well, not really so practical) problem, Davies has to weave together several different threads into a discussion that is primarily about relativistic spacetime. There were a few places where this felt awkward. For example, the section on how to 'inflate' a virtual wormhole up to macroscopic size gets interrupted by a grabbag listing of possible sources for exotic (negative energy) matter. This list is very interesting but feels as if it were crammed into a space too small for it. ( )

Sketchy but authoritative, and short, account of time-related implications of relativity.