Hello! This is the Doctor. Here's a book all about my faithful friend, K9. As you know, K9 is a kind of robot dog—though he'd sooner be described as a completely-mobile, self-powered computer with multi-sensory circuits and built-in defensive capabilities! I'll also be telling you about some other amazing mechanical creatures I've encountered on my travels through Space and Time—some have been surprisingly friendly, but others were very dangerous indeed...