About Twin Cities APT Mission Statement To promote the understanding and ethical use of psychological type and the MBTI®, to improve the understanding of ourselves and others, and to enhance the effectiveness of people working together. Guiding Principles Twin Cities APT is guided by the desire to provide a forum for interaction among those interested in psychological type. Read More Operating Principles Twin Cities Association for Psychological Type is guided by a set of operating principles. The first: Membership in TC-APT is open to all those interested in type. Read More History of Twin Cities APT TC-APT was started to expand the awareness of the MBTI and promote its use in the Twin Cities area. Susan Brock and Shirley Dahlen pioneered the beginnings of the chapter. Read More