  Conventional perturbative QCD calculations on the production of a heavy quark
``$H$'' consist of two contrasting approaches: the usual QCD parton formalism
uses the zero-mass approximation ($m_H=0$) once above threshold, and treats $H$
just like the other light partons; on the other hand, most recent ``NLO'' heavy
quark calculations treat $m_H$ as a % large parameter and always consider $H$
as a heavy particle, never as a parton, irrespective of the energy scale of the
physical process. By their very nature, both these approaches are limited in
their regions of applicability. This dichotomy can be resolved in a unified
general-mass variable-flavor-number scheme, which retains the $m_H$ dependence
at all energies, and which naturally reduces to the two conventional approaches
in their respective region of validity. Recent applications to lepto- and
hadro-production of heavy quarks are briefly summarized.
