The doctrine of attention is the nerve of the whole psychological sys tem, and that as men judge of it, so shall they be judged before the general tribunal of psychology." That was Titchener (95) speaking, and leaving lit tle doubt about the centrality of the concept of attention at the time that psychology was formed. Titchener spoke as a Structuralist. Though the Functionalists had a different view of the nature of attention, they agreed on the concept's importance. After the turn of the century, however, atten tion was almost totally ignored in psychology; it had little or no place in the behavioristic, gestalt, or psychoanalytic positions. Only in the 1950's was in terest in the concept renewed. Work since has progressed enough to justify this first chapter on attention in the Annual Review of Psychology.In stating the view of the Functionalists, William James could write that "Every one knows what attention is" (39) , but it does not appear that sim ple to present-day reviewers. Moray (67) has listed six familiar categories of attention-mental concentration, vigilance, selective attention, search, ac tivation, and set-and has suggested that Neisser's (72) recent treatment of analysis-by-synthesis may be a seventh. We focus here on two of these cate gories-as it happens, two that exhibit continuity with the earliest theoreti cal positions. The first is "selective attention," which is what the Functional ists thought attention was all about. The emphasis is on the process of the organism's choosing to notice a particular part of his environment. The sec ond is "vigilance," or "sustained attention." The historical connection here is less direct, but the emphasis is on the result of the attentive process, or the "sensory clearness," that was stressed by the Structuralists.Recent interest in these two aspects of attention was largely stimulated by work done in England, primarily at the Applied Psychology Research Unit in Cambridge. Broadbent's (2) and Cherry's (11) experiments in spired many others on selective attention to speech stimuli. Our review of this work takes its starting point in 1958 after the publication of Broad-