Behavior therapy “cut its teeth” on phobias. Since Wolpe’s (1958) pioneering book on the treatment of neurotic problems a variety of behavioral procedures have been tested and proven effective in the treatment of phobia. During the 1960’s and 1970’s scores of studies were performed isolating the effective ingredients of these treatments. The overriding conclusion that emerged from this systematic research during the 1970’s was that one particular procedure was common to all successful behavioral treatments for phobia (Mavissakalian & Barlow, 1981). This procedure, which came to be called exposure, consisted of motivating the patient to expose him or herself to a series of increasingly more difficult situations that provided the context for the phobic reactions and arranging conditions to facilitate this exposure. At present there are many psychologically based theories as to why this treatment is successful, including but not limited to extinction, habituation, emotional processing, and increases in perceived self-efficacy (Barlow & Mavissakalian, 1981; Barlow, in press). While none of these theories is fully supported as yet, there is clear evidence that exposure-based treatments are effective with phobias in general and agoraphobia with panic in particular. Some of these data are represented in Table 5.1 which summarizes the results of 24 controlled outcome studies testing exposure-based treatments for agoraphobia as reviewed by Jansson & Öst (1982). The data summarized in this review indicate that 70 percent of patients improved substantially with exposure-based treatments. The dropout rate averages 12 percent, although it is consistently higher for the type of exposure program which is administered in a very intensive fashion, for example, over a 2-week period, and much lower for programs administered in a more gradual self-paced manner (e.g., Barlow, O’Brien, & Last, 1984).