Abstract : This is a longitudinal study of changes in the Navy's official and unofficial personnel policies during the twentieth century. Data were gathered along a number of dimensions at 10-year intervals from 1900 to 1980. The emergence of new enlisted ratings is documented, along with changes in the non- judicial punishment system. Conclusions are drawn as to the reasons for the development of a training system; changes in recruitment strategies and manning; and variations in the handling of discipline. Changes in one area of the Navy 'matrix' are seen as having effects on many other parts of the system. Key dimensions studied are: organization structure, good order and discipline, recruitment, training, advancement, rewards and recognition, retirement, assignment and rotation, leave and liberty, uniform regulations, and authority. The study brings into question a number of assumptions about the past, including the effectiveness of the 'Old Navy' discipline, the status and role of the warrant officer, and the cultural patterns related to uniform and grooming regulations.