This 1974 book is a personal survey by an eminent linguist of most branches of linguistics, setting out its position, questioning some underlying assumptions, and in general testing the adequacy of descriptive theories. Though the underlying theory is basically that of transformational-generative linguistics, there are many queries and disagreements, some of which might be called structuralist in a broad sense, or even taxonomic. The particular problems chosen are those which have forced themselves on Professor Householder during a lifetime of reading, teaching and writing about linguistics, including the justification of linguistic research itself.