  A review of the status of lattice simulations in particle physics
phenomenology is presented. Recent computations of leptonic decay constants of
light and heavy mesons, and of the Isgur-Wise function relevant for
semi-leptonic decays of $B$-mesons, are discussed in some detail. Calculations
of other quantities are briefly outlined. The systematic errors inherent in
lattice simulations, and procedures to reduce and control them, are described.
