  We discuss a proposal to measure the Casimir force in the parallel plate
configuration in the $1-10\mu$m range via a high-sensitivity torsional balance.
This will allow to measure the thermal contribution to the Casimir force
therefore discriminating between the various approaches discussed so far. The
accurate control of the Casimir force in this range of distances is also
required to improve the limits to the existence of non-Newtonian forces in the
micrometer range predicted by unification models of fundamental interactions.
