  The production of J/Psi's in nuclei is re-examined and the critical role of
Feynman x distributions in the study of photoproduction and hadronic production
of both J/Psi's and Drell-Yan dimuons is expatiated. The need to consider both
initial and final state interactions and the key effect of initial state
interactions on the total J/Psi cross section are demonstrated.
  We use a Woods-Saxon Monte Carlo simulation to obtain distributions of the
numbers of collisions prior and subsequent to the charmonium production. With
those results we relate the mean number of nucleon-nucleon collisions, $<n>$ to
$A^{1/3} + B^{1/3}$, and give a new analytic functional form for the A
dependence of the suppression.
  Finally we carry out a full Monte Carlo calculation of S, including an
initial state prior energy loss in keeping with the measured Feynman x
distributions in $\pi$-A and p-A interactions. We use an energy loss
parameterization which is consistent with the energy loss from minimum bias
data fitted in ISAJET. We also use an open charm absorption cross section,
$\sigma_{oc}$, constrained from photoproduction of J/Psi's, to analyze the
latest data on the J/Psi suppression. The role of color screening, the time
evolution of off-shell charmonium to the on-shell J/Psi, and the energy
dependence of the charmonium-nucleon inelastic and absorption cross sections
are discussed. We find no anomalous suppression when comparing our results to
published data.
