NONPERTURBATIVE CONTRIBUTIONS TO THE INCLUSIVE RARE DECAYS B-]X(S)GAMMA AND B-]X(S)L(-)()L()

We discuss nonperturbative contributions to the inclusive rare B decay s B-->X(s)gamma and B-->X(s)l+l-. We employ an operator product expans ion and the heavy quark effective theory to compute the leading correc tions to the decay rate found in the free quark decay model, which is exact in the limit m(b)-->infinity. These corrections are of relative order 1/m(b)2, and may be parametrized in terms of two low-energy para meters. We also discuss the corrections to other observables, such as the average photon energy in B-->X(s)gamma and the lepton invariant ma ss spectrum in B-->X(s)l+l-.