Determining the chemical abundances is a key part in understanding the
evolution and nature of high redshift galaxies. We can only measure
metallicities with spectroscopic observations but since galaxies
become increasingly faint with redshift we have to rely on stacking of
many galaxy spectra or use scaling relations that are derived from
observations of low redshift galaxies. Alternatively we can use
observations of strong gravitational lensed galaxies where the flux
from background sources allow us to check that the scaling relations
are also valid in the high redshift universe.
We can also analyse metallicities more accurately from absorption
lines either in quasar or gamma-ray burst spectra. These lines of
sight randomly probe intervening material, and provide different means
for measuring galaxy metallicities. Only recently have we found the
connection of how metallicities derived in emission correlate with
those in absorption. In this talk I will review recent analyses of the
metallicities in high redshift galaxies based on different
observational techniques, and recent efforts in combining information
from galaxies seen in emission and absorption.