Abstract
Lattice QCD provides a first-principles approach to calculating hadronic
matrix elements. These are required to infer from experimental data some
of the fundamental parameters of the Standard Model, or any
Beyond-the-Standard Model. The first part of this talk briefly reviews
the main ideas involved in lattice Monte Carlo calculations, while the
second focuses on how lattice and experimental data combine to constrain
quark-flavour-changing parameters such as the CKM matrix element Vcb.