Because of the rising interest in the relevance of psychology to missions, a number of empirical studies have been completed which address various issues pertaining to missionary selection, stress, and ongoing functioning. This paper presents a critique and synthesis of the empirical literature relevant to missionary selection, stress, and functioning. The research under review here was limited and was mostly preliminary or descriptive in nature. However, several conclusions can be made at both a clinical level and a practical level. In terms of missionary selection, successful candidates have been found to demonstrate good interpersonal skills, flexibility/adaptability, and a history of emotional stability. Missionaries have also been found to suffer from the effects of stress, but are often hesitant to disclose their feelings of stress and burnout. Missionary stress appears to originate from two sources: interpersonal and job factors. Lastly, missionaries have been found to be no more pathological in their functioning than the normal population. However, results concerning the influence of depression on a missionary's ability to persevere on the field remain inconclusive. It is argued that research pertaining to missionaries must move from its current disjointed approach to one that incorporates collaboration and coordination of efforts. (RJM)