Introduction.- The Symmetry of Electromagnetism with Respect to Electric and Magnetic Charges.- The Landau-Ginzburg Model of a Dual Superconductor.- Abelian Gauge Fixing.- The Confinement of SU (3) Color Charges.- Vectors, Tensors and Their Duality Transformations.- The Relation Between Minkowski and Euclidean Actions.- The Generators of the SU (2) and SU (3) Groups.- Color Charges of Quarks and Gluons.