The student of aboriginal legends and customs, after reading the many monographs that have been printed about other Pueblo Indians, notably the Hopi and Zuñi, is inclined at first to think himself fortunate to find a field so little worked as Ácoma. Even Cochití and Laguna have opened windows of understanding to the white investigator. One soon finds that Ácoma has not been neglected, but that every one attempting to go beyond the most superficial glance arrives at a wall as blank of entrance as the ancient lower story of its own fortress dwellings. The ladders of admission to its hatchways hardly give the stranger more than uncertain glimpses here and there within the obscure interior, and these are so fragmentary and elusive, often contradictory, that he can affirm little about their ritual life—which is the core of tribal existence. Of all Indians the Ácomas seem most resentful of intrusive questioning and most unwilling to impart, even for purposes of record, any real knowledge of themselves. Certain clans and rituals are already extinct. It has, however, seemed worth while, before the old life has become something less than a memory, overspun by all the vagueness of tradition, to bring together into one small volume the substance of everything already written about Ácoma. Such historical data as have come to light are followed by a few legends and folk-tales—fairy tales perchance some of them are—and then by the researches of scholars like Bandelier, Fewkes, Parsons and Hodge. It may be thought that the legitimate bounds of the subject as given in the title have been too far exceeded. In explanation it is but fair to state that since Ácoma is still well-nigh impenetrable to any foreigner, the only way to apprehend its mental and spiritual development is to use inferentially whatever seems permissible from related tribes. In justification of this method I am happily supported by no less an authority than the distinguished anthropologist, Dr. Kroeber, who writes: “That the pueblo civilization was substantially the same in every town has always been assumed; it begins to be evident that a great part of it has been borrowed back and forth in the most outright and traceable manner. The history of the cults and institutions of any one of these people simply cannot be understood without a knowledge of the others. The problem in its very nature is a comparative one, and until the pueblo languages are more thoroughly understood there is no solution.”