The notes taken by Saussure's student Emile Constantin were not available to the editors of the published Cours de linguistique générale (1916), and came to light only after the second world war. They have never been published in their entirety. The third and last course of lectures, of which Constantin kept this very full record, is generally considered to represent a more advanced version of Saussure's teaching than the earlier two. It is clear that Constantin's notebooks offer a text which differs in a number of significant respects from the Cours published by Saussure's original editors, and bring forward ideas which do not emerge in the 1916 publication. They constitute unique evidence concerning the final stages of Saussure's thinking about language. This edition of the notes is accompanied by an introduction and a full English translation of the text. There has been no attempt made by Komatsu and Harris, to turn the English into readable prose. Constantin's notes, even as revised by their author, retain the infelicities, repetitions, abruptness - occasionally incoherences - that betray the circumstances of their origin. The volume constitutes an important landmark in the history of modern linguistics and provides essential documentation for all scholars and libraries specializing in the subject.