The second edition of Anxiety and Its Disorders is not merely an updating of the original edition, published in 1988; it is an entirely new book. It consists of two main parts. The first comprises eight chapters that present Barlow’s theoretical views on fear, panic, and anxiety, cast within the context of emotion theory. The second part comprises seven chapters, each co-written with another author, usually one of Barlow’s Boston University colleagues. In addition to a chapter on diagnostic classification, each covers one of the anxiety disorders. Theoretical themes developed in the first part are continued in the second part, and Barlow’s "voice" is evident throughout. The influence of co-authors is most apparent in the issues emphasized. For example, the chapter on posttraumatic stress disorder concentrates on assessment, the specialty of coauthor Terence M. Keane.