Background and personality characteristics which are associated with successful team teaching were investigated for this study. Members of 31 secondary school teaching teams were rated by judges (who were principals, deans, and college consultants) individually and as teams on the bases of 10 background characteristics and eight personality characteristics, and completed a 16-factor personality questionnaire which included the personality characteristics on which they were rated. Also, a rating scale for each teacher, based on the 16 factors of the personality questionnaire, was completed by his school principal. Chi square analyses and tests of significance of the data showed that successful teaching team members held a higher degree, were teaching in their major field, and were more cooperative, stable, aggressive, enthusiastic, adventurous, shrewd, experimental, and self-controlled. In addition, it was found that school principals could not accurately assess personality traits necessary for effective team performance; therefore, critical performance scores for each personality factor examined in this study were identified to be used in selecting and assigning teachers to teams. (The first half of this report consists of a review of the literature concerning team teaching.) (SP)