[or she] will do…They draw lines about, and segregate, an otherwise chaotic environment; they are our methods for finding our way about in an ambiguous universe." Gordon W. Allport, 1935, p. 806 It has been nearly 70 years since Gordon Allport famously declared the attitude "the most distinctive and indispensable concept in contemporary American social psychology" (Allport, 1935, p. 798). In the decades since this bold claim, a large literature has accumulated generally reinforcing the notion that attitudes often do, as Allport (1935) suggested, profoundly influence perception, cognition, and behavior. Equally clear from this literature, however, is that attitudes do not always do so. That is, although some attitudes exert a powerful impact on thinking and on behavior, others are largely inconsequential. Similarly, whereas some attitudes are tremendously durable, resisting change in the face of a persuasive appeal and remaining stable over long spans of time, others are highly malleable and fluctuate greatly over time.The term "attitude strength" is often used to capture this distinction, and researchers have identified roughly a dozen attributes of attitudes that are associated with their strength (see .These strength-related attitude attributes include attitude importance, knowledge, elaboration, certainty, ambivalence, accessibility, intensity, extremity, structural consistency, and others. A large literature now exists documenting the relations of these attitude attributes with the four defining features of strong attitudes (i.e., resistance to change, stability over time, and a powerful impact on thought and on behavior; . For example, attitudes to which people attach more personal importance are better predictors of behavior (e.g., Budd, 1986;Parker, Perry, & Gillespie, 1974;Rokeach & Kliejunas, 1972), more resistant to change (Fine, 1957;Gorn, 1975;Zuwerink & Devine, 1996), and more powerfully influence liking of other people (Byrne, London, & Griffitt, 1968;Clore & Baldridge, 1968;Granberg & Holmberg, 1986;Krosnick, 1988b;McGraw, Lodge, & Stroh, 1990), inferences about others' personality traits (Judd & Johnson, 1981), and many other cognitive processes. Similar sorts of relations have been documented between other strength-2 related attitude attributes and the four defining features of strong attitudes (for a review, see . But considerably less is known about the relations among the strength-related attitude attributes themselves. In fact, a controversy has emerged in the attitude literature in recent years regarding the underlying structure of these attributes.In this chapter, we review this controversy and the empirical evidence and conceptual assumptions that have fueled it. We then draw on a diverse set of recent studies to shed new light on the conceptual and practical utility of the competing perspectives. Finally, we consider the implications of our findings for the conceptualization of attitude strength and for the methods by which it is studied. We begin below by defining each strength-rela...