"The Langlands Program was initiated by Robert Langlands in the late 1960s in order to connect number theory and harmonic analysis [L1]. In the last 40 years a lot of progress has been made in proving the Langlands conjectures, but much more remains to be done. We still do not know the underlying reasons for the deep and mysterious connections suggested by these conjectures. But in the meantime, these ideas have propagated to other areas of mathematics, such as geometry and representation theory of infinite-dimensional Lie algebras, and even to quantum physics, bringing a host of new ideas and insights. There is hope that expanding the scope of the Langlands Program will eventually help us get the answers to the big questions about the Langlands duality. ... [L1] R. Langlands, Problems in the theory of automorphic forms, in Lect. Notes in Math. 170, pp. 18–61, Springer Verlag, 1970."