  We have used an extended version of the Cascade-Exciton Model (CEM) to
analyze more than 600 excitation functions for proton induced reactions on 19
targets ranging from C-12 to Au-197, for incident energies ranging from 10 MeV
to 5 GeV. We have compared the calculations to available data, to calculations
using approximately two dozen other models, and to predictions of several
phenomenological systematics. We present here our conclusions concerning the
relative roles of different reaction mechanisms in the production of specific
final nuclides. We comment on the strengths and weaknesses of the CEM and
suggest possible further improvements to the CEM and to other models.
