Karl Friston is a theoretical neurobiologist and Professor of Neuroscience at University College London. He is also an honorary consultant at UCL’s Queen Square Institute of Neurology and is a fellow of both the Academy of Medical Sciences and the Royal Society. He also happens to be the most cited neuroscientist in the world. Karl kindly read and gave a blurb for the book: “A remarkably current and forward-looking treatment. This book uses all my favourite words—in the right order—and some I have never encountered before. It offers a delightful narrative, grounded in state-of-the-art thinking about what it is to be an observer or, in the author's words, BEING IS BELIEVING.”