  ISM comprises multiple components, including molecular, neutral, and ionized
gas, and dust, which are related to each other mainly through star formation -
some are fuel for star formation (molecular gas) while some are the products of
it (ionized gas, dust). To fully understand the physics of star formation and
its evolution throughout cosmic time, it is crucial to measure and observe
different ISM components of galaxies out to high redshifts. I will review the
current status of near-IR studies of galaxies during the peak of star formation
activity (z~1-3). Using rest-frame optical emission lines, we measure dust,
star formation, and gaseous properties of galaxies. JWST will advance such
studies by probing lower luminosities and higher redshifts, owing to its
significantly higher sensitivity. Incorporating ALMA observations of cold dust
and molecular gas at z>1 will give us a nearly complete picture of the ISM in
high-redshift galaxies over a large dynamic range in mass.
