Participant observation is approached by considering five strategies of participation, as reflected in the writings of field workers in the social sciences. The strategies considered are: (1) gaining access to data, (2) evoking behavior, (3) identifying psychologically with the people being studied, (4) connecting concepts with indicators, and (5) formulating hypotheses. For each strategy, cases are cited to illustrate the range of participation procedures included in it, and each strategic rationale is examined critically. Evidence from the cases supports the conclusion that different modes of participation are appropriate for different aspects of scientific field work.