These are the notes of a set of four lectures which I gave at the 2012 CERN Summer School of Particle Physics. They cover the basic ideas of gauge symmetries and the phenomenon of spontaneous symmetry breaking which are used in the construction of the Standard Model of the Electro-Weak Interactions.
We trace the origin of the concept which was named by the High Energy Physics Community The Cabibbo angle
We review our expectations in the last year before the LHC commissioning.
I will argue that the same kind of reasoning, which led us to predict the opening of a new chapter in hadron physics, may shed some light on the existence of new physics at the as yet unexplored energy scales of LHC.
