  We present a brief overview on some of the most significant achievements
obtained by means of NMR and muSR techniques in highly frustrated magnets.
First the basic quantities measured by the two techniques will be presented and
their connection to the microscopic static and dynamical spin susceptibility
recalled. Then the main findings will be outlined, starting from the most
simple frustrated units, the molecular nanomagnets, to artificially built
frustrated systems as $^{3}$He on graphite, to magnets with a macroscopically
degenerate ground-state as the ones on a pyrochlore or kagom\'e lattices.
