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 contribution towards building up the stellar masses of galaxies, can now be directly measured using these data.