The expression "learning disabilities" is widely used and easily understood, but it may be applied to various handicaps. The author discusses the details of one particular handicap—reading disability—with implications that apply to the whole group in general. He emphasizes the concept that the fundamental basis of specific reading disability or dyslexia is usually found in inherent maturational lags rather than in brain damage or environmental influences. Although developmental lags do produce brain dysfunction, the author states the objections to the use of such terms as "brain damage" and "minimal brain dysfunction," which connote brain pathology. The concept of developmental lags is more accurate and more constructive.