Recent research has repeatedly led to connections between important
rigidity questions and bounded cohomology. However, the latter has
remained by and large intractable. This monograph introduces the
functorial study of the continuous bounded cohomology for topological
groups, with coefficients in Banach modules. The powerful techniques of
this more general theory have successfully solved a number of the
original problems in bounded cohomology. As applications, one obtains,
in particular, rigidity results for actions on the circle, for
representations on complex hyperbolic spaces and on Teichmüller spaces.
A special effort has been made to provide detailed proofs or references
in quite some generality.