This program of research was aimed at investigating a novel application of computer aided text analysis (CATA). To date, CATA has been used in a wide variety of disciplines, including Psychology, but never in the area of personnel selection. Traditional personnel selection techniques have met with limited success in the prediction of costly training failures for some occupational groups such as pilot and air traffic controller. Accordingly, the overall purpose of this thesis was to assess the validity of linguistic style to select personnel. Several studies were used to examine the structure of language in a personnel selection setting; the relationship between linguistic style and the individual differences dimensions of ability, personality and vocational interests; the validity of linguistic style as a personnel selection tool and the differences in linguistic style across occupational groups. The participants for the studies contained in this thesis consisted of a group of 810 Royal Australian Air Force Pilot, Air Traffic Control and Air Defence Officer trainees. The results partially supported two of the eight hypotheses; the other six hypotheses were supported. The structure of the linguistic style measure was found to be different in this study compared with the structure found in previous research. Linguistic style was found to be unrelated to ability or vocational interests, although some overlap was found between linguistic style and the measure of personality. In terms of personnel selection validity, linguistic style was found to relate to the outcome of training for the occupations of Pilot, Air Traffic Control and Air Defence Officer. Linguistic style also demonstrated incremental validity beyond traditional ability and selection interview measures. The findings are discussed in light of the Five Factor Theory of Personality, and motivational theory and a modified spreading activation network model of semantic memory and knowledge. A general conclusion is drawn that the analysis of linguistic style is a promising new tool in the area of personnel selection.