From Laplace to Langlands via representations of orthogonal groups

In the late 1960s, Robert Langlands proposed a new and far-reaching connection between the representation theory of Lie groups over real and -adic fields, and the structure of the Galois groups of these fields [24]. Even though this local Langlands correspondence remains largely conjectural, the relation that it predicts between representation theory and number theory has profoundly changed our views of both fields. Moreover, we now know enough about the correspondence to address, and sometimes solve, traditional problems in representation theory that were previously inaccessible. Roughly speaking, the local Langlands correspondence predicts that complex irreducible representations of a reductive group over a local field should be