2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/1934A summary is given of the calibration of the Cepheid scale required in the derivation of distances from observations at V and I, as in the HST work on extragalactic Cepheids. There is some evidence that a small metallicity correction may be necessary in deriving distances in this way. The evidence for this comes both from observations of Cepheids of different metallicities and from a comparison of the LMC distance modulus derived from Cepheids and that derived by other methods.9 pages, no figures, to appear in IAU Symp 201Astrophysicstext