This paper proposes a field procedure for collecting data at stationary mass rallies. Noting the research gap in adequate data about ongoing gatherings, we present a set of techniques summarized under the name zone-sector strategies. We emphasize area sampling, dividing the crowd into zones and sectors, and collecting data during stationary phases of assemblages. We also employ two-member interview teams, in an effort to collect reliable information about attitudinal and nonvisible characteristics of participants during the demonstration itself. Methods of testing reliability and validity of information are presented. Data from four political rallies exemplify the techniques and basically support the validity of the zone-sector approach. We conclude by stating possible uses and advantages of the methods. Social researchers have shown interest in the difficult problem of collecting data at sporadic demonstrations and other gatherings (e.g., Evans; Milgram and Toch). Some have noted the general lack of good data on crowd behavior (Berk: a, b). Others have pointed out the difficulties inherent in research on crowds and the pitfalls of the techniques most commonly used, such as sideline observation and retrospective questioning (e.g., Couch; Fisher; McPhail, a). Recent attempts to gather data have stressed primarily the stationary phase of crowds or assemblages. They have paid attention to improving observation. Fisher suggested a dramaturgical framework for such observation (see Ponting). Others (McPhail, b; McPhail and Pickens) have been developing a photographic method for observing crowd processes, with emphasis on at least momentary participant alignment. Jacobs has figured out how to calculate the size of a relatively stationary crowd, again using photographic observation. While these observational techniques and recent general guidelines for research (e.g., Lofland; Quarantelli and Dynes; Schatzman and Strauss) have advanced the methods of gathering data as collective episodes occur, new techniques could still be profitable. The lack of data about crowds themselves, mentioned by Berk (b, 15) persists. In particular, the field of collective behavior needs a *This research was supported in part by funds made available through a National Science Foundation Science Development grant to the University of North Carolina at Chapel Hill. We are very grateful to Glen H. Elder, N. David Milder, E. L. Quarantelli, Timothy J. Curry, and John S. Reed for helpful comments on earlier drafts. We also express our appreciation to the following interviewers: Edward Arroyo, Greg Bird, Habibullah Dada, Suzann Frey, Marg Gainer, Carol Goldsmith, Linda Harris, Marsha Hill, Evon Kruse, Roxi Ann Liming, Ken Long, Jane McCaskey, Frank McIntyre, Christine Nelms, Steven Rinehart, Anne Sykes, Darlene Walker, and Barbara Werner.