Lattice matrix elements are briefly reviewed. In the quenched approximation $f_B$, $B_B$ and $B_K$ are now under good control. Experimental hints for $f^{ \rm expt}_{ D_S}> f^{ \rm QQCD}_{ D_S}$ are noted; precise determination of $f_{ D_S}$ from experiment as well as from the lattice is strongly advocated. Lattice calculations of the form factor for $B\to\pi\ell\nu$ at relatively large value of $q^2$ have made good progress and should be useful in conjunction with precise measurement of the differential spectra expected from $B$-factories. Recent attempt at $K\to \pi\pi$ using staggered quarks is briefly discussed; use of non-perturbative renormalization, improved actions and operators with staggered quarks is emphasized. Due to the good chiral behavior of domain wall quarks it would be useful to study $K\to \pi\pi$ with this discretization.
Categories: hep-ph