  I review recent lattice results in kaon physics, particularly in the
determination of V_{us} and the B_K parameter of K^0-\bar{K}^0 mixing. I use
lattice data to argue for the need of developing SU(2)_L \times SU(2)_R chiral
perturbation theory for kaon physics and discuss some recent progress in
achieving this. In particular it is shown that for K_{\ell 3} decays at q^2=0
(where q is the momentum transfer between the kaon and the pion), the chiral
logarithms can be calculated in spite of the fact that the external pion
carries half the energy of the kaon (in the kaon's rest frame), because these
logarithms arise from soft internal loops. Future prospects, including
applications to K\to\pi\pi decays are discussed. The need to define and exploit
renormalization schemes which can simultaneously be implemented numerically in
lattice simulations and used in higher-order perturbative calculations is
explained.
