Phenomenology From Lattice QCD

I review two subjects in which lattice simulations are making, or can make in the future, a significant contribution to particle physics phenomenology. The first subject is the evaluation of quantities which enter into the determination of the vertex $A$ of the unitarity triangle from experimental measurements of decay rates and mixing amplitudes. These quantities include the form-factors for semileptonic B-decays, the leptonic decay constants of the $B$ and $B_s$ mesons and the $B$-parameters for $B_{d}$-$\bar B_{d}$ and $B_{s}$-$\bar B_{s}$ mixing and the corresponding parameter for $K$-$\bar K$ mixing, $B_K$. In the second part of this talk I will review the status and prospects for the evaluation of $K\to\pi\pi$ amplitudes and for the subsequent study of the $\Delta I=1/2$ rule and the evaluation of $\epsilon^\prime/\epsilon$.