  The NASA/ESA/CSA James Webb Space Telescope (JWST) will be the successor to
the Hubble Space Telescope and may be launched as early as mid-2011. The key
scientific goals for JWST are discovering and understanding the formation of
the first stars and galaxies, the evolution of galaxies and the production of
elements by stars, and the process of star and planet formation. Within this
context, we discuss the expected properties of the first stellar generations in
the Universe. We find that it is possible to discern truly primordial
populations from the next generation of stars by measuring the metallicity of
high-z star forming objects. The very low background of JWST will enable it to
image and study first-light sources at very high redshifts, whereas its
relatively small collecting area limits its capability in obtaining spectra of
z~10--15 first-light sources to either the bright end of their luminosity
function or to strongly lensed sources. With a suitable investment of observing
time JWST will be able to detect individual Population III supernovae, thus
identifying the very first stars that formed in the Universe.
