  We briefly review the observational and theoretical investigations on Very
Low Mass (VLM) stars. New evolutionary computations, extending toward the lower
main sequence previous computations already given for globular cluster stars,
are presented. Comparisons with updated observational data both for globular
cluster stars and VLM stars with known parallaxes are also shown. We discuss
observational evidences supporting theoretical predictions concerning the Color
- Magnitude (C-M) location of faint Main Sequence stars as far as concern the
dependence of the lower main sequence on the metallicity.
