As Michael Silverstein discusses in his introduction to this new edition, the two foundational essays presented here are culminating moments in the scholarly history of North American indigenous peoples' languages and cultures. Franz Boas's "Introduction" essay (1911) initiates readers into the collection of grammatical sketches contained in the multiple volumes of the Handbook of American Indian Languages, underscoring critical issues of language in human cognition and its role in sociocultural variation. Twenty years earlier, J. W. Powell published "Indian Linguistic Families of America North of Mexico" to accompany his Seventh Annual Report of the Bureau of American Ethnology (BAE) of the Smithsonian Institution. Powell interpreted the BAE's vast collection of vocabularies through a classificatory perspective like those of geology, geography, and biology, thus organizing understanding of the hundreds of attested languages as members of linguistic families. Originally published in the same volume in 1966, these two essays form a cornerstone of modern indigenous language studies.