Light-quark masses and renormalons

A brief review of the problem of the determination of light-quark masses from QCD sum rules for the correlators of scalar and pseudoscalar currents is given. Special attention is paid to the description of the large-$N_f$ results, obtained in collaboration with Broadhurst and Maxwell, for the scalar correlator, and estimates of its higher-order perturbative uncertainties within the renormalon-inspired large-$\beta_0$ expansion in the $\overline{\rm MS}$ scheme are given. Brief discussion is presented of the results of calculations of higher-order perturbative QCD corrections to the relation between pole and $\overline{\rm MS}$-scheme running-quark masses. Their comparison with the different estimates is also given.