This book challenges contemporary direct realist theories of perception and defends a version of the causal theory that the author locates in the critical realist tradition of which Wilfrid Sellars is the main recent exponent. The author highlights the difficulties direct realists face in providing a coherent positive account of their view. He develops an analysis of perceptual experience derived from the later writings of Sellars. According to this account experience involves both low-level concepts and a distinct sensory component. This view makes sense of the various notions of nonconceptual content appealed to in current discussion, and provides, in addition, solutions to the conceptual problems raised by recent experimental work on attention and change-blindness. An important feature of this theory is the dynamic navigational account of perception and action, which points to an underlying continuity between common sense, scientific and philosophical accounts of perceiving.