Properties of Spiral and Elliptical Galaxy Progenitors at z > 1

We present the results of a Hubble Space Telescope and ground-based optical and near-infrared study to identify progenitors of spirals and ellipticals at z > 1. We identify these systems through photometric and spectroscopic redshifts, deep K-band imaging, stellar mass measurements, and high resolution imaging. The major modes of galaxy formation, including major mergers, minor mergers, and accretion of intergalactic gas, and their relative contributions towards building up the stellar masses of galaxies, can now be directly measured using these data