1. Introduction -- 1. Collective decisions and power structure -- 2. Social choice -- 3. Games and game forms -- 4. The effectivity functions of a game form -- 5. Effectivity functions and cooperative games -- 6. An overview of the book -- 7. Notes -- 2. The structure of effectivity functions -- 1. Introduction -- 2. Fundamental concepts -- 3. Polarity -- 4. Selected families of effectivity functions -- 5. Topological effectivity functions -- 6. Notes -- 3. Stability -- 1. Introduction -- 2. The core of an effectivity function -- 3. Stable effectivity functions -- 4. Stability of convex effectivity functions -- 5. Acyclicity and stability -- 6. Stable veto functions -- 7. Notes -- 4. Implementation -- 1. Introduction -- 2. Implementation of social choice correspondences by game forms -- 3. Monotonic social choice functions -- 4. Notes -- 5. Implementation in strong Nash equilibrium -- 1. Strong Nash equilibrium -- 2. The effectivity functions of a strongly Nash implementable social choice correspondence -- 3. The fundamental theorem -- 4. The nucleus -- 5. The supernucleus -- 6. The subcore -- 7. A characterization of strong Nash implementable social choice correspondences -- 8. Notes -- 6. Exact and strong consistency -- 1. Self-implementation -- 2. Successive elimination and exact and -- consistency -- 3. The Holzman conditions -- 4. Notes -- 7. Implementation in coalition proof Nash equilibrium -- 1. Coalition proof Nash equilibrium -- 2. Implementation in coalition proof Nash equilibrium -- 3. Uniform domination -- 4. U-effectiveness and indirect u-domination -- 5. Notes -- 8. Other effectivity functions -- 1. Introduction -- 2. The ?-effectivity function -- 3. Cooperative equilibria of type 1 -- 4. Equilibria of type 2 and 3 -- 5. Notes -- 9. Value of effectivity functions -- 1. Introduction -- 2. Effectivity functions with convex feasible sets -- 3. Correlated strategies and effectivity functions -- 4. Effectivity functions of repeated games -- 5. Notes -- References.