Supersymmetry is one of the boldest, most original and most fruitful ideas to appear in physics in a very long time. In common with nonabelian gauge theories and spontaneous symmetry breaking, it has great depth, and just like those ideas it has travelled quite a way on its own momentum, without carving out for itself a rockbed of supporting experimental evidence. Guided by these analogies, nobody doubts that when discarding some blinding prejudices, or coming by some new data, supersymmetry will come into its own, experimentally as well.

Unlike nonabelian gauge theories and spontaneous symmetry breaking, supersymmetry does not build on well-understood mathematics. Rather, it has created its own, rich, truly new mathematics. Yes, we are faced here with one of those rare instances, when the mathematicians, in all their wisdom, have overlooked a beautiful and most useful structure, and come to appreciate it only at the demand of physicists. We are living in an era in which the contacts between mathematicians and physicists are being vigorously renewed (particularly through work in supersymmetry and gauge theories). This is a good omen, since such contacts have historically always led to great advances both in mathematics and physics.