, 1929^1997Emerson Foulke saw the world with a rare clarity, comprehension, and humor that enriched the experience of others. He lacked sight, physiologically defined, but he did not lack vision.Writing as three friends, we recount stories and anecdotes about Emerson's achievements in using alternatives to vision for perceiving the world and accomplishing the tasks of daily living. Writing as three fellow students of perception, we describe some of the central ideas of his research and writings. We wish to call attention to Emerson's ideas about strategies for perceiving, and hope that these ideas and examples may inform a better understanding of perception, lead to research on the guidance of action and comprehension without vision, and inspire others öboth sighted and blindöin the better use of their own resources for perceiving the world. His observations, research, and insights benefitted a wide audience. We write now in an effort to expand that audience.Emerson Emerson Foulke began his study of experimental psychology when the mainstream of sensory and perceptual research was focused on vision by passive observers in static situations. When his studies ended, the mainstream had shifted and widened, with much greater interest in dynamic stimulation associated with moving objects and moving observers, in exploratory actions, in the perceptual functions of sensory systems, and in nonvisual perception. These changed directions in perceptual research were reflected in the work of the Perceptual Alternatives Laboratoryöeg on perception and comprehension of large-scale spaces; on active exploration of space by walking, touching, and wielding a long cane; on reading by touching and listening; and on the design of perceptual interfaces between human perceivers and sources of spatial and symbolic information. Many of Foulke's ideas about perception, action, and comprehension were ecological. His conceptions were shaped by the problems he researched and by his experiences in perceiving and acting in the world without vision. The following list summarizes what we understand as some of the key ideas developed in Foulke's research and writings.Perception is an active process temporally organized by observers interacting with their surroundings. As Gibson (1979) noted, perceiving and acting are a cycle: One perceives in order to act, and acts in order to perceive. Nowhere is the``acting in order to perceive'' part of the cycle more clear than in situations where one is exploring the world without vision. Consider wielding a long cane to explore unfamiliar terrain, scanning with the hand to read Braille, and walking to discover the salient features and landmarks of unfamiliar surroundings and learn their spatial layout.