In Ten Short Lessons in Time Travel, Brian Clegg takes us on a fascinating and up-to-date tour of the workings of the universe that suggest the possibility of journeying back and forth through time. Einstein's special theory of relativity made time travel to the future a possibility, and later his general theory of relativity showed us that loops in spacetime could exist, meaning that we might be able to bend time backwards, too. But what are the practicalities of making time travel possible? What do we still need to know? How do we deal with any paradoxical twists in time - and could quantum physics hold the answer?