  This paper discusses the current uncertainties in luminosity calibration of
the RR Lyrae variables. The difference in distance moduli between the SMC and
LMC as derived from RR Lyrae stars and classical Cepheids is used to estimate a
metallicity effect on the Cepheid PL(VI) relation of 0.29+-0.11 mag/dex. There
is evidence that suggests RR Lyrae variables and type II Cepheids share a
common K-log(P) relation. Metallicity and age gradients in the LMC are
discussed from data on RR Lyrae variables and AGB stars.

Solar and Stellar Astrophysics