Perception is the first form of representational mind to emerge in evolution. Three types of form are discussed: formal representational structure of perceptual states, formation characteristics in computations of perceptual states, and the form of the visual and visuomotor systems. The book distinguishes perception from non-perceptual sensing. The formal representational structure of perceptual states is developed via a systematic semantics for them—an account of what it is for them to be accurate or inaccurate. This semantics is elaborated by explaining how the representational form is embedded in an iconic format. These structures are then situated in what is known about the processing of perceptual representations, with emphasis on formation of perceptual categorizations. Features of processing that provide insight into the scope of the perceptual (paradigmatically visual) system are highlighted. Relations between these processes and associated perceptual-level capacities—conation, attention, memory, anticipation, affect, learning, imagining—are delineated. Roughly, a perceptual-level capacity is one that borrows its form and content from perception and involves processing that is no more complex or sophisticated than processing that occurs in the classical visual hierarchy. Relations between perception and these associated perceptual-level capacities are argued to occur within the perceptual and perceptual-motor systems. An account of what it is to occur within these systems is elaborated. An upshot is refinement of the distinction between perceptual-level capacities, on one hand, and thought and conception, on the other. Intermediate territory between perception-level representation and propositional thought is explored. The book is resolutely a work in philosophy of science. It attempts to understand perception by focusing on its form, function, and underlying capacities, as indicated in the sciences of perception, rather than by relying on introspection or ordinary talk about perception.