This volume contains twelve of my game-theoretical papers, published in the period of 1956-80. It complements my Essays on Ethics, Social Behavior, and Scientific Explanation, Reidel, 1976, and my Rational Behavior and Bargaining Equilibrium in Games and Social Situations, Cambridge University Press, 1977. These twelve papers deal with a wide range of game-theoretical problems. But there is a common intellectual thread going though all of them: they are all parts of an attempt to generalize and combine various game-theoretical solution concepts into a unified solution theory yielding one-point solutions for both cooperative and noncooperative games, and covering even such 'non-classical' games as games with incomplete information. SECTION A The first three papers deal with bargaining models. The first one discusses Nash's two-person bargaining solution and shows its equivalence with Zeuthen's bargaining theory. The second considers the rationality postulates underlying the Nash-Zeuthen theory and defends it against Schelling's objections. The third extends the Shapley value to games without transferable utility and proposes a solution concept that is at the same time a generalization of the Shapley value and of the Nash bargaining solution.