  I describe very briefly the new libraries of empirical spectra of stars
covering wide ranges of values of the atmospheric parameters Teff, log g,
[Fe/H], as well as spectral type, that have become available in the recent
past, among them the HNGSL, MILES, UVES-POP, ELODIE, and the IndoUS libraries.
I show the results of using the IndoUS and the HNGSL libraries, as well as an
atlas of theoretical model atmospheres, to build population synthesis models.
These libraries are complementary in spectral resolution and wavelength
coverage, and will prove extremely useful to describe spectral features
expected in galaxy spectra from the NUV to the NIR. The fits to observed galaxy
spectra using simple and composite stellar population models are discussed.
