2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45392This is the written version of four lectures given at the 1994 TASI. My aim is to explain the essentials of lattice calculations, give an update on (though not a review of) the present status of calculations of phenomenologically interesting quantities, and to provide an understanding of the various sources of uncertainty in the results. I illustrate the important issues using the examples of the kaon B-parameter ($B_K$) and various quantities related to $B$-meson physics. Contents: 1. Why do we need lattice QCD? 2. Basics of Euclidean Lattice Field Theory. 3. Discretizing QCD. 4. Simulations. 5. Numerical Results from quenched QCD. 6. Anatomy of a calculation: $B_K$. 7. Heavy mesons on the lattice. 8. A final flourish69 pages, latex (uses epsf and psfig), 22 postscript figures includedHigh Energy Physics - PhenomenologyHigh Energy Physics - Latticetext