  This paper is an attempt to better understand Tamarkin's approach of
classical non-displaceability theorems of symplectic geometry, based on the
microlocal theory of sheaves, a theory whose main features we recall here. If
the main theorems are due to Tamarkin, our proofs may be rather different and
in the course of the paper we introduce some new notions and obtain new results
which may be of interest.
