Preface.- L.A. Caffarelli: The Monge-Ampère equation and Optimal Transportation, an elementary view.- G. Buttazzo, L. De Pascale: Optimal Shapes and Masses, and Optimal Transportation Problems.- C. Villani: Optimal Transportation, dissipative PDE's and functional inequalities.- Y. Brenier: Extended Monge-Kantorowich Theory.- L. Ambrosio, A. Pratelli: Existence and Stability results in the L1 Theory of Optimal Transportation.