  This contribution describes the difficult task of inferring the IMF from
local star-count data, by discussing the mass-luminosity relation, unresolved
binary, triple and quadruple systems, abundance and age spreads and Galactic
structure, all of which must be accounted for properly for the results to be
meaningful. A consensus emerges that the local IMF may be represented by a
two-part power-law, with indices alpha=1-1.5 for stars with mass m<0.5 Msun,
and the Salpeter value alpha=2.3 for more massive stars, but some uncertainties
remain. Notable is also that the sensitivity of the stellar luminosity function
(LF) to the derivative of the mass-luminosity relation is very evident in the
(local) Hipparcos and HST, open-cluster and globular-cluster LFs, thus allowing
tests of stellar structure theory. The upcoming astrometry space missions DIVA
and GAIA will undoubtedly lead to significant advances in this field.
