All criticism in question with regard to the actual significance of North American pictographs is still better met by their practical use by historic Indians for important purposes, as important to them as the art of writing, of which the present paper presents a large number of conclusive examples. It is also known that when they now make pictographs it is generally done with intention and significance. Even when this work is undertaken to supply the demand for painted robes as articles of trade it is a serious manufacture, though sometimes imitative in character and not intrinsically significant. All other instances known in which pictures are made without original design, as indicated under the several classifications of this paper, are when they are purely ornamental; but in such cases they are often elaborate and artistic, never the idle scrawls above mentioned. A main object of this paper is to call attention to the subject in other parts of the world, and to ascertain whether the practice of pictography does not still exist in some corresponding manner beyond what is now published. A general deduction made after several years of study of pictographs of all kinds found among the North American Indians is that they exhibit very little trace of mysticism or of esotericism in any form. They are objective representations, and cannot be treated as ciphers or cryptographs in any attempt at their interpretation. A knowledge of the customs, costumes, including arrangement of hair, paint, and all tribal designations, and of their histories and traditions is essential to the understanding of their drawings, for which reason some of those particulars known to have influenced pictography are set forth in this paper, and others are suggested which possibly had a similar influence. Comparatively few of their picture signs have become merely conventional. A still smaller proportion are either symbolical or emblematic, but some of these are noted. By far the larger part of them are merely mnemonic records and are treated of in connection with material objects formerly and, perhaps, still used mnemonically. It is believed that the interpretation of the ancient forms is to be obtained, if at all, not by the discovery of any hermeneutic key, but by an understanding of the modern forms, some of which fortunately can be interpreted by living men; and when this is not the case the more recent forms can be made intelligible at least in part by thorough knowledge of the historic tribes, including their sociology, philosophy, and arts, such as is now becoming acquired, and of their sign-language.