Anxiety is one of those entltles which everyone "knows," but which ultimately resists simple objective description. The essence of the phenomenon is its subjectivity. True it has its well documented associated physiological events: the increased pulse rate and blood pressure, sweating, and so on, but each of these phenomena may also be part of physical exertion, fear, or even pleasurable excitement. They cannot fully define the sense of threat, danger, collapse, malignancy in greater or smaller amount, in greater or lesser locali sation, with more or less objective evidence for its validity...