  Improved $B$ meson decay data have permitted more incisive tests of
factorization predictions. A concurrent benefit is the ability to constrain the
Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$. Using a simultaneous fit
to differential distributions $d \Gamma(\ob \to D^{*+} l^- \bar \nu_l)/ dq^2$
measured by the CLEO and LEP Collaborations, the rates for the color-favored
decays $\ob \to D^{(*)+} (\pi^-,\rho^-,a_1^-)$, and the rate for $\ob \to D^+
l^- \bar \nu_l$, we find $|V_{cb}| = 0.0415 \pm 0.0022$. The slope of the
universal Isgur-Wise form factor is described by a parameter found to be $\rs =
1.52 \pm 0.11$. Taking the $D_s$ meson decay constant from the world average of
direct measurements, we predict satisfactorily the branching ratios for $\ob
\to D^{(*)+} D_s^{(*)-}$. Ratios of helicity amplitudes for color-favored
processes are also found to be in accord with predictions.
