  We study the behavior of the "underlying event" in hard scattering
proton-antiproton collisions at 1.8 TeV and compare with the QCD Monte-Carlo
models. The "underlying event" is everything except the two outgoing hard
scattered "jets" and receives contributions from the "beam-beam remnants" plus
initial and final-state radiation. The data indicate that neither ISAJET or
HERWIG produce enough charged particles (with PT > 0.5 GeV/c) from the
"beam-beam remnant" component and that ISAJET produces too many charged
particles from initial-state radiation. PYTHIA which uses multiple parton
scattering to enhance the "underlying event" does the best job describing the
data.
