This book was first published in 1968; it has been reprinted several times and has been translated, so far, into 12 languages; and it is still as widely used today in colleges and universities throughout the world as it was twenty years ago. The fact that this is so is of course very gratifying. It is, however, something that I never anticipated when I wrote the book.

It has been suggested to me that one of the reasons why Introduction to theoretical linguistics (ITL) has become something of a classic (the term is not mine) is that in writing it I took a broader view of the subject-matter than the authors of most other textbooks of the period and emphasized, as they did not, continuity rather than discontinuity in the development of what I referred to in the original Preface as contemporary linguistic theory: continuity between philology and linguistics; between traditional grammar and modern (i.e., mid-twentieth-century) linguistics; between structuralism (European and American) and generativism.

It is arguable that, at certain points and in certain respects, I overemphasized continuity. I did not appreciate the degree to which my view of linguistics had been shaped by my own academic background, which included a training in classical philology and philosophy, on the one hand, and a certain amount of formal and computational linguistics, on the other, and by my own research interests.