Philosopher Ned Block argues in this book that there is a "joint in nature" between perception and cognition and that by exploring the nature of that joint, one can solve mysteries of the mind. The first half of the book introduces a methodology for discovering what the fundamental differences are between cognition and perception and then applies that methodology to isolate how perception and cognition differ in format and content. The second half draws consequences for theories of consciousness, using results of the first half to argue against cognitive theories of consciousness that focus on prefrontal cortex. Along the way, Block tackles questions such as: Is perception conceptual and propositional? Is perception iconic or more akin to language in being discursive? What is the difference between the format and content of perception, and do perception and cognition have different formats? Is perception probabilistic, and if so, why are we not normally aware of this probabilistic nature of perception? Are the basic features of mind known as "core cognition" a third category in between perception and cognition? This book explores these questions not by appeals to "intuitions," as is common in philosophy, but to empirical evidence, including experiments in neuroscience and psychology. This is an open access publication, available online and distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International licence (CC BY-NC-ND 4.0), a copy of which is available at http://creativecommons.org/licenses/by-nc-nd/4.0/. Enquiries concerning use outside the scope of the licence terms should be sent to the Rights Department, Oxford University Press.