This paper SUM the relatively unsuccessful effort to relate hypnotizability to sex, age, psychiatric diagnoses, suggestibility, and various personality traits. The problems of measurement, subject selection, controls, and experimenter biss are reviewed. Comparison of data iS diflicuIt and replication of studies infrequent. This might be a t tributed to incomplete reporting of methodology, to defects in experimental design, and to various conceptual problems. Concepts which view hypnotizability as a "something" universal, a "something" unique, or a "nothing" are briefly appraised. Finally, hypnotizability is seen as a "term" describing a relationship between a "route" and a "state"-h identifiable by merawable criteria. This paper summarizes the older experimental literature on hypnotizability, last reviewed extensively by Weitzenhoffer in 1953, but focuses on more recent reports. Other reviews include Bramwell (1903) ) Hull (1933), and the less comprehensive reviews of Pattie (1956a), Weitzenhoffer,S and Young (1926;. Although hypnotizability generally refers to the observation that only certain individuah can be hypnotized, definitions of hypnotizability vary so considerably from paper to paper that the approach here is to accept each definition as it is advanced in a given report.3