  What follows is an updated version of the lectures given at the CERN Academic
Training (November 1993) and at the Jaca Winter Meeting (February 1994). The
aim is to provide a pedagogical introduction to the Standard Model of
electroweak interactions. After briefly reviewing the empirical considerations
which lead to the construction of the Standard Model Lagrangian, the particle
content, structure and symmetries of the theory are discussed. Special emphasis
is given to the many phenomenological tests (universality, flavour-changing
neutral currents, precision measurements, quark mixing, etc.) which have
established this theoretical framework as the Standard Theory of electroweak
interactions.
