During the second half of the twentieth century we made an enormous progress in understanding the nature of matter's elementary constituents and the interactions among them.
This progress led to the construction of an elaborate edifice, known as "The Standard Model". It is a quantum field theory with a gauge invariance under U(1)xSU(2)xSU(3). This model has been enormously successful in predicting new phenomena and in describing with great accuracy the experimental results. It should not be called any more "The Standard Model" but instead "The Standard Theory". In this talk we will review the present status of this Standard Theory and the arguments which indicate that we should try togo beyond it.
Prof. John Iliopoulos, Ecole Normale Superieure