The principal goal of my research is to understand the astrophysics that regulates star formation and galaxy growth. Absorption-line spectroscopy of distant light sources (quasars/gamma-ray burst afterglows) offers a powerful probe for studying diffuse gas over a wide range of physical conditions, from low-density intergalactic medium, to high-density star-forming regions. My main research interest is to connect dark clouds revealed in absorption spectra to stars identified in deep galaxy surveys, in order to understand the recycling of baryons between star-forming regions and intergalactic space.  Current projects include: