A key question in modern science is to explain how the present-day universe of galaxies evolved from the initial conditions measured in the micro-wave background at recombination. Over the next 5 years I propose to undertake a major program of research to address this issue, by discovering and studying directly the progenitors of today's massive galaxies during the first ~2 billion years of cosmic history, and hence performing critical tests of current theories of galaxy formation. It is now clear that to sample representative volumes of the high-redshift universe requires ultra-deep near-infrared, mid-infrared and sub-mm surveys covering over ~1 sq. degree. Until now this has not been possible, but this field is about to be revolutionized by the introduction of a new generation of wide-field facilities in the next year. Specifically, 2009 will see the commissioning of the new near-infrared VISTA survey telescope in Chile, the new SCUBA2 sub-mm camera on the JCMT in Hawaii, the far-infrared Herschel Space Observatory, and the near-infrared camera WFC3 in the Hubble Space Telescope. Now, through my leadership of the deepest of the new generation of wide-field infrared and submm surveys to be undertaken with these revolutionary new facilities, I am unusually well-placed to take an integrated approach to the study of galaxy formation/evolution reaching back, for the first time, into the epoch of re-ionisation, at redshifts z ~ 7 - 10. Through this application I request the level of support required to exploit these new and unique data in what is one of the most important and topical areas at the forefront of modern astronomical research. Investment in this research program will also help ensure that European astronomers are strongly positioned to exploit the James Webb Space Telescope (JWST), the Atacama Large Millimetre Array (ALMA), and future large telescopes (e.g. E-ELT) to study the physics of galaxy formation over virtually all of cosmic history.