Game theory has served as a standard text for game theory courses since the publication of the first edition in 1968. The fourth edition updates several recently developed subfields. It has been enlarged by adding a new section dealing with the controversial "Monty Hall problem", showing how the solution can be easily obtained by using game theoretic methods; rather than those of conditional probability theory. A new chapter discusses the work of recent Nobel Laureates: this includes, on the one hand, Hurwicz, Maskin and Myerson's work on mechanism design, and on the other hand, Roth's work on auctions and two-sided matchings -- P. 4 of cover.