  Multijet events at large transverse energy (sum E_T > 420 GeV) and large
multijet invariant mass (M_jets > 600 GeV) have been studied by the CDF
Collaboration at the Fermilab Tevatron. The observed jet multiplicity
distribution can be understood in a QCD inspired exponentiation model, in
regions of phase space which require going beyond fixed order perturbation
theory.
