Cain emphasizes the indissoluble links between pleasure and anxiety. In the literature we find an opposition between anxiety and pleasure. Anxiety is sometimes presented as the outcome of unsuccessful strivings for pleasure. But, clinically, the two are not that separate. Pleasure, as many theorists have noted, is never complete, and there are situations in which anxiety can become invested with pleasure, as Freud noted in his discussion of the pleasurable effects of heightened tension. Cain also sees a problem in the distinction between the fear of a real danger and anxiety before a real danger. Fear becomes anxiety when linked to ambivalence, i.e., attraction, as in the fear of heights. Cain considers three clinical examples of this link between pleasure and anxiety in humor, in hysteria, and in masochism. He concludes with a discussion of the various mechanisms by which this intrinsic link between anxiety and pleasure can take place.