  The role lattice QCD can play in $B$ physics is surveyed. We include results
for the decay constant, and discuss upcoming calculations of semileptonic form
factors and neutral-meson mixing. Together with experimental measurements,
these calculations can determine the unitarity triangle. Plenary talk presented
at the Workshop on $B$ Physics at Hadron Accelerators, Snowmass, Colo., 21
June--2 July, 1993.
