  In recent years the precision of lattice calculations has improved hugely,
and the results are making a very significant impact in particle physics
phenomenology. Indeed there is no alternative general method which can be used
in the evaluation of nonperturbative strong interaction effects for a wide
variety of physical processes. In this talk I discuss a selection of topics in
flavour physics, including \textit{mature} quantities for which lattice
calculations have been performed for a long time (e.g. the determination of the
$V_{us}$ CKM matrix element and $B_K$), quantities which we are now learning to
study (e.g. $K\to\pi\pi$ decays amplitudes and the spectrum and mixing of
$\eta-\eta^\prime$ mesons) and important phenomenological quantities for which
a large amount of experimental data is available but which we do not yet
understand how to approach in lattice simulations (e.g. nonleptonic B-decays).
The improvement in precision and the extension of the range of processes which
can be studied using lattice QCD has to be continued vigorously if precision
flavour physics is to play a complementary role to large $p_\perp$ discovery
experiments at the LHC in unravelling the next level of fundamental physics.
