We report results of a search for B --> tau nu in a sample of 9.7 x 10(6) c
harged B meson decays. We exclusively reconstruct the companion B decay to
suppress background. We set an upper limit on the branching fraction B(B --
> tau nu) < 8.4 X 10(-4) at 90% confidence level, We also establish B(B+/-
--> K+/- nu <(nu )over bar >) < 2.4 X 10(-4) at 90% confidence level.