  Phases of elements of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be
obtained using decays of $B$ mesons to $\pi^+ \pi^-$, $\pi^\pm K^\mp$, and
$\pi^+ K^0$ or $\pi^- \overline{K}^0$. For $B^0~{\rm or}~ \overline{B}^0 \to
\pi^+ \pi^-$, one identifies the flavor of the neutral $B$ meson at time of
production and studies the time-dependence of the decay rate. The other
processes are self-tagging and only their rates need be measured. By assuming
flavor SU(3) symmetry and first-order SU(3) breaking, one can separately
determine the phases $\gamma \equiv {\rm Arg}~V_{ub}^*$ and $\alpha = \pi -
\beta - \gamma$, where $\beta \equiv {\rm Arg}~V_{td}^*$. Special cases include
the vanishing of strong interaction phase differences between amplitudes, the
possibility of recovering partial information when $\pi^+ \pi^-$ and $\pi^\pm
K^\mp$ decays cannot be distinguished from one another, and the use of a
correlation between $\gamma$ and $\alpha$ in the region of allowed parameters.
