Abstract Theory of Schwarz Methods.- Two-Level Overlapping Methods.- Substructuring Methods: Introduction.- Primal Iterative Substructuring Methods.- Neumann-Neumann and FETI Methods.- Spectral Element Methods.- Linear Elasticity.- Preconditioners for Saddle Point Problems.- Problems in H (div ; ?) and H (curl ; ?).- Indefinite and Nonsymmetric Problems.- Elliptic Problems and Sobolev Spaces.- Galerkin Approximations.- Solution of Algebraic Linear Systems.