Precision Determination of the Cabibbo-Kobayashi-Maskawa Element Vcb

We extract the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element V-cb and the most relevant parameters of the heavy quark expansion from data of inclusive semileptonic B decays. Our calculation includes the recently computed O(alpha(s)Lambda(2)(QCD)/m(b)(2)) corrections and a careful estimate of the residual theoretical uncertainty. Using a recent determination of the charm quark mass, we obtain \V-cb\ = (42.21 +/- 0.78) x 10(-3) and m(b)(kin) (1 GeV) = (4.553 +/- 0.020) GeV.