Gibson and Pick argue that infants are active learners who perceptually engage their environments and extract information from them. This ecological approach to development - defined as a 'theory about perceiving by active creatures who look and listen and move around' - was spearheaded by the Gibson and Gibson in the 1950s. This book, written by one of the most eminent experimental psychologists of the 20th Century, is the summary and capstone of a long and fruitful experimental tradition.