Alexander Wendt's book, Social Theory of InternationalPolitics, is published twenty years after Kenneth Waltz's enormouslyinfluential Theory of International Politics. The similarity in their titles is nocoincidence, since Wendt wants to build on the insights of Waltz'srealism and construct an idealist and holist account ofinternational politics (not, note, international relations). In my view,Wendt's book is likely to be as influential as Waltz's. It is asuperbly written and sophisticated book, one that has clearly been drafted andredrafted so as to refine the argument and anticipate many of the likelyobjections. I think that although I can anticipate the objections of both hisrationalist and his reflectivist critics. I am also aware that he makes lifedifficult for them by defining his ground very precisely, and by trying to definethe terms of any debate in which he might be engaged. Criticism of the book isnot an easy task. The book is likely to become the standard account for thoseworking within the social constructivist literature of International Politics. Itis a book that has been eagerly awaited, and it will not disappoint those whohave been waiting for Wendt to publish his definitive statement onconstructivism.