  The Casimir effect is a crucial prediction of Quantum Field Theory which has
fascinating connections with open questions in fundamental physics. The ideal
formula written by Casimir does not describe real experiments and it has to be
generalized by taking into account the effects of imperfect reflection, thermal
fluctuations, geometry as well as the corrections coming from surface physics.
We discuss these developments in Casimir physics and give the current status in
the comparison between theory and experiment after years of improvements in
measurements as well as theory.
