Data are presented in a series of events which occurred during the 18-month study period and which are analyzed in terms of consequences for task performance, social relations, and individual stress. The study describes the emergence and the functioning of two competing and sometimes conflicting cultures within the department: the 'street cop culture,' which organizes individual officers and precinct social networks into a social system, and the 'management cop culture.' The two are bureaucratically juxtaposed and while there is some uneasy accommodation between them the two cultures are increasingly in conflict which serves to isolate the precinct level from the headquarters level. The result is disaffection, strong stress reaction, increasing attrition, and growing integrity problems. The precinct social organization model, which takes its values from street cop culture, is described in a model containing four major structures which socialize officers into the precinct organization and relate them to each other and to headquarters. Officers learn the culture and organize their behavior in terms of a Cop's Code of rules. The rules explain how to relate to peers and the job and how to deal with the bosses. Recommendations and implications of the study are discussed. Appendixes include the patrol precinct organization, NYCPD rules and regulations, NYCPD patrol duties and responsibilities, and about 75 references. Footnotes are given. (Author abstract modified)