Much has happened in the five years since I finished the first edition of this book. Linguistics has advanced, the cognitive sciences have exploded, the world has become ever more dangerous, and Chomsky has continued to lead a dual existence as academic and activist.

To take account of all these changes is impossible. I have left the basic plan of the book unchanged, but I have made many additions and amendments. First, I have corrected mistakes where I have become aware of them, and attempted to clarify points which were unclear. Second, I have updated the notes and references where that has been within my ability. As no one can be master of all the disciplines touched on here, I have concentrated on updating those sections pertaining to areas where Chomsky's recent work has been directly relevant. As a result, the bibliography contains entries for about forty new works by Chomsky himself: over fifteen new or revised books, and another twenty-five new articles. At the same time, the secondary literature on Chomsky has also burgeoned: major works have appeared by Antony & Hornstein (2003), McGilvray (1999), Mitchell & Schoeffel (2002), Winston (2002), and many others. These, as well as about a hundred other new entries are likewise included and, where relevant, I have simultaneously expanded the notes to include reference to these new items.

Third, I have attempted to give some indication of how the field and the world have changed since 1998. Chomsky has continued to produce seminal work in linguistics, and I have revised the relevant sections of Chapter 2 and added some discussion of developments in Minimalism accordingly. This has entailed making a number of modifications to the first edition, where I had failed to lay the relevant groundwork for some of the issues that now occupy center-stage. I have also updated the discussion of evolution, another area where Chomsky has produced interesting new work. Most obviously, I have added a section on the events of September 11, 2001 and their aftermath – “9-11” – which have overwhelmingly preoccupied Chomsky's time and energy. These revisions and extensions have necessitated other minor changes throughout the book.