High redshift Ly-alpha emitting galaxies (LAEs) are presently our best candidates for galaxies "in the act of formation". We have been studying the photometric,spectroscopic, and morphological properties of these objects in the redshift range 2 < z < 3 using a variety of methods, including ground-based imaging, HST imaging, optical spectroscopy, and near-IR spectroscopy. I will describe the results of our observations, detail how the LAE population evolves in luminosity, mass, size, and dust content, show that these unique objects are likely the progenitors of the Milky Way-type galaxies of today. I will also describe how Ly-alpha emitters in the redshift range 1.9 < z < 3.5 will be used to measure the evolution of Dark Energy via the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX).