Lagrangian Theory of Classical Fields

Instead of a regular introduction to the theme Classical Fields, this chapter can be seen as a continuation of Chap. 1 , in the sense that classical field equations are obtained from guessing appropriate Lagrangians, with the help of imagination and symmetry properties of space-time, in order to use them in the context of Hamilton’s principle. The need of including time as a new coordinate is discussed for relativistic and non-relativistic fields.