  The properties of fluctuation induced interactions like van der Waals and
Casimir-Lifshitz forces are of interest in a plethora of fields ranging from
biophysics to nanotechnology. Here we describe a general approach to compute
these interactions. It is based on a combination of methods from statistical
physics and scattering theory. We showcase how it is exquisitely suited to
analyze a variety of previously unexplored phenomena. Examples are given to
show how the interplay of geometry and material properties helps to understand
and control these forces.
