Almost fifty years after he first crossed the small screen, Doctor Who remains a science fiction touchstone. His exploits are thrilling, his world is mind-boggling, and that time travel machine – known as the Tardis – is almost certainly an old-fashioned blue police box once commonly found in London.

Paul Parsons’s plain-English account of the real science behind the fantastic universe portrayed in the Doctor Who television series provides answers to such burning questions as whether a sonic screwdriver is any use for putting up a shelf, how Cybermen make little Cybermen, where the toilets are in the Tardis, and much more.

Taking the show as a starting point – episode-by-episode in some cases – Parsons dissects its scientific concepts. In addition to explaining why time travel is possible and just how that blue police box works, Parsons

discusses who the Time Lords are and how we may one day be able to regenerate just like them ponders the ways that the doctor’s two hearts might work and introduces us to a terrestrial animal with five details the alien populations and cosmology of the Whovian Universe and relates them to what we currently know about our universe compares the robotics of the show with startlingly similar real-world applications.

This slender, almost equation-free discussion is penned by a Ph.D. cosmologist and is ideal beach reading for anyone who loves science and watches the show – no matter which planet the beach is on.