Multiplicity one theorems in representation theory

An important question of Representation Theory is "what happens to an irreducible representation of a group when one restricts it to a subgroup?". Usually it stops being irreducible and it is interesting to know whether it decomposes to distinct irreducible representations. This report contains an exposition on this question and a short description of a recent proof that in the case of the pair (GL(n+1),GL(n)) over local fields the answer is positive.