  The ratio of partial decay rates for charged and neutral $B$ mesons to $K
\pi$ final states provides information on the weak phase $\gamma \equiv {\rm
Arg} (V_{ub}^*)$ when augmented with information on the CP-violating asymmetry
in the $K^\pm \pi^\mp$ mode. The requirements for a useful determination of
$\gamma$ are examined in the light of present information about the decays $B^0
\to K^+ \pi^-$, $B^+ \to K^0 \pi^+$, and the corresponding charge-conjugate
modes. The effects of electroweak penguins and rescattering corrections are
noted, and proposals are made for estimating and measuring their importance.
