  We discuss a program for systematic studies of heavy quark production in
$pp$, $pA$ and $AA$ interactions. The $Q \bar Q$ production cross sections
themselves cannot be accurately predicted to better than 50% at RHIC. For
studies of deviations in $Q \bar Q$ production such as those by nuclear
shadowing and heavy quark energy loss, the $pp$ cross section thus needs to be
measured. We then show that the ratio of $pA$ to $pp$ dilepton mass
distributions can provide a measurement of the nuclear gluon distribution. With
total rates and nuclear shadowing under control it is easier to study energy
loss and to use $c \bar c$ as a normalization of $J/\psi$ production.
