  Hadronic B decays containing an parity-even charmed meson in the final state
are studied. Specifically we focus on the Cabibbo-allowed decays $\bar B\to
D^{**} \pi(\rho), D^{**}\bar D_s^{(*)}, \bar D^{**}_sD^{(*)}$ and $\bar B_s\to
D_s^{**}\pi(\rho)$, where $D^{**}$ denotes generically a p-wave charmed meson.
The $B\to D^{**}$ transition form factors are studied in the improved version
of the Isgur-Scora-Grinstein-Wise quark model. We apply heavy quark effective
theory and chiral symmetry to study the strong decays of p-wave charmed mesons
and determine the magnitude of the $D_1^{1/2}-D_1^{3/2}$ mixing angle. Except
the decay to $D_1(2427)^0\pi^-$ the predictions for $B^-\to D^{**0}\pi^-$ agree
with experiment. The sign of $D_1^{1/2}-D_1^{3/2}$ mixing angle is found to be
positive in order to avoid a severe suppression on the production of
$D_1(2427)^0\pi^-$. The interference between color-allowed and color-suppressed
tree amplitudes is expected to be destructive in the decay $B^-\to
D_1(2427)^0\pi^-$. Hence, an observation of the ratio
$D_1(2427)^0\pi^-/D_1(2427)^+\pi^-$ can be used to test the relative signs of
various form factors as implied by heavy quark symmetry. Although the predicted
$B^-\to D_1(2420)^0\rho^-$ at the level of $3\times 10^{-3}$ exceeds the
present upper limit, it leads to the ratio
$D_1(2420)\rho^-/D_1(2420)\pi^-\approx 2.6$ as expected from the factorization
approach and from the ratio $f_\rho/f_\pi\approx 1.6$ . Therefore, it is
crucial to have a measurement of this mode to test the factorization
hypothesis. For $\bar B\to \bar D_s^{**}D$ decays, it is expected that $\bar
D_{s0}^*D\gsim \bar D_{s1}D$ as the decay constants of the multiplet
$(D_{s0}^*,D_{s1})$ become the same in the heavy quark limit.
