Black holes. What even are they? In brief, a black hole is a region of spacetime so curved by gravity that even light cannot escape it. They're peculiar objects - and notoriously difficult to understand - but are actually a fascinating fusion of the simple and the complex. Although the mathematics describing their behaviour is fiendishly difficult, we can explore the subject by starting with basic principles and straightforward thought experiments. Read on to uncover what's inside a black hole, how scientists discovered this amazing phenomena, even what to do if you find yourself falling into one... and since no one is likely to turn up and help (you'll find out why), what you need to do to escape! Common myths about black holes are dispelled, there is guidance on how to win several Nobel prizes, and the eventual fate of the entire Universe is revealed (maybe)... A little bit of time travel might also be involved!