Results revealed that the existing research on the motivations and personalities of bombers is anecdotal, descriptive, and conjectural. The four existing descriptions of various bombers used varying methods, present overlapping types in some cases. In addition, none of these descriptions have been tested with respect to reliability or validity other than the investigator's personal experience. Thus, all the research on bombers rests on expert authority rather than on science. Findings indicated the need for a Federally funded research effort that incorporates structured interviews, history gathering, and psychological and physiological tests of incarcerated bombers. This research should be theoretically guided by the concordance between the known motivations and behavior of bombers and the concurrent and predictive validity of the construct, psychopathology. Figure and 46 references (Author abstract modified)