The discussion is now nearly forty years old, if we date it from the appearance of Mr. J. F. McLennan’s _Primitive Marriage_ in 1865. Yet, in spite of the speculations of some and the explorations of other distinguished students, the main problems are still in dispute. Was marriage originally non-existent? Was promiscuity at first the rule, and, if so, what were the origins, motives, and methods of the most archaic prohibitions on primitive license? Did man live in ‘hordes,’ and did he bisect each ‘horde’ into exogamous and intermarrying moieties, and, if he did, what was his motive? Are the groups and kindreds commonly styled ‘totemic’ earlier or later than the division into a pair of moieties or ‘phratries’? Do the totem-kins represent the results of an early form of exogamous custom, or are they additions to or consciously arranged subdivisions of the two exogamous moieties? Is a past of ‘group marriage’ or ‘communal marriage’ proved by the terms for human relationships employed by many backward races, and by survivals in manner and custom? These are among the questions examined in the introductory chapters that may be read either before or after Mr. Atkinson’s _Primal Law_. To him I am indebted for the conception of sexual jealousy as a powerful element in the evolution of exogamy. Since my attention was first directed to these topics, I have felt that a clear and consistent working hypothesis of the origin of totemism was indispensable, and such an hypothesis, with a criticism of other extant theories, is here offered. Throughout I have attempted to elucidate and bring into uniformity the perplexing and confused special terms employed in the discussion. Here it should be explained that by ‘marriage’ in this work I mean permanent cohabitation of man and woman, sanctioned by tribal custom, and usually preceded by some rite or initiation which does not prelude to casual amours. By family or fire circle I mean the partners to this permanent cohabitation, their offspring, and such kinsfolk by blood or affinity as may be members of their camp. In the first sentence of the book I speak of the family as ‘most ancient and most sacred,’ and I do so deliberately. The primitive association described I take, with Mr. Darwin and Mr. Atkinson, to be ‘most ancient,’ and to be the germ of the historic family, which is ‘most sacred.’ But to ‘sacred’ when I apply the word to the primitive fire-circle I give no religious sense, such as the Greek hearth enjoyed under Hestia, youngest and oldest daughter of Zeus. I mean that the rules given to the primitive fire-circle by the sire were probably the earliest and the most stringent, though not yet sanctioned by a tabu or a goddess. Such a small circle, and not a promiscuous horde or commune, I conceive, with Mr. Darwin and Mr. Atkinson, to have been the earliest form of human society.