  The ability of present and future experiments to test the Standard Model in
the $B$ meson sector is described. We examine the loop effects of new
interactions in flavor changing neutral current $B$ decays and in $Z\to b\bar
b$, concentrating on supersymmetry and the left-right symmetric model as
specific examples of new physics scenarios. The procedure for performing a
global fit to the Wilson coefficients which describe $b\to s$ transitions is
outlined, and the results of such a fit from Monte Carlo generated data is
compared to the predictions of our two sample new physics scenarios. A fit to
the $Zb\bar b$ couplings from present data is also given.
