We consider a system of particles confined in a box in d-dimension interacting
via a tempered and stable potential. We prove the validity of the cluster expansion
for the canonical partition function in the high temperature - low density regime.
The convergence is unifor in the volume and in the thermodynamic limit it reproduces
Mayer's virial expansion providing an alternative and more direct derivation which
avoids the deep combinatorial issues present in the original proof.