The materials for this work were collected during the past forty years, commencing during explorations in Central Australia, where I came into close and friendly contact with two tribes who were in a condition of complete savagery. Circumstances later on enabled me to acquire considerable influence over tribes in South - East Australia, and to become acquainted with their sacred ceremonies and be present at them.

In 1873 I joined Dr. Lorimer Fison in investigating the classificatory system of relationships which obtains among these savages. In connection with this inquiry, our attention was directed to the tribal class system, and the rules of marriage and descent connected therewith.

In these investigations we were assisted by correspondents living in places scattered over the greater part of Eastern Australia, and in a less degree in the western half. Without their aid it would not have been possible to have brought together the collection of facts which was necessary to enable us to draw sound conclusions as to the real character of the organisation and beliefs of the native tribes.

In the course of our work we found the conclusions to which we were led regarding the system of relationships, the character and origin of the tribal and social organisation, and the rules of marriage and descent, brought us into conflict with hypotheses as to primitive society and its organization and development advanced by certain leaders of anthropological thought.