The Scientific Secrets of Doctor Who
This was a fresh twist on the genre, though, with a short story featuring one of the Doctors preceding each chapter. And as well as the predictable speculations about the possibility of time travel and life on other planets, there were thoughtful discussions of ageing and death, regeneration, war and artificial intelligence, as well as many other subjects. The short stories were pretty good, too, so that was a bonus.
This was an intelligent introduction to a wide range of scientific topics, gently connected to the stories and mythos of Doctor Who -- though you'd need to be a Who tragic like myself to understand all the references. Younger converts might struggle -- or it might encourage them to check out Old Who, which is not a bad thing! I really enjoyed this book, and it was one of the better examples of the genre I've come across. Perfect for the young geek in your life. Or a slightly older one!