Before attempting the comparative analysis of the various age class systems and their models, it may be useful to sketch the systems' geographical distribution and briefly review the anthropological approach to their study.

I must first admit that even today we do not have an exhaustive ethnographic picture of societies with age class systems. In describing the development of the anthropological studies of such systems, I do not intend to evaluate critically all that has been written on the subject. Rather, my intent is to identify the major issues raised in the study of age class systems.

The geographical distribution of age class systems

The kind of social organization represented by age class systems is not very widely distributed ethnographically, but it is not rare by any means. In reality, recognition of the specific structure and significance of these systems was slow in coming.

Although the first news of an age class system goes back to the end of the seventeenth century and involved one of the most interesting and complex systems, the gada system of the Oromo Galla, the institutional nature of the system was not appreciated. Difficulty in interpretation was augmented by the fact that age class systems were always found together with an acephalous society, with these acephalous societies only being understood and studied rather late in the day. The most recent research projects and analyses have painted a composite ethnographic picture that has been extended to all continents.