Thanks to deep NIR imaging from both Hubble/WFC3 (e.g. XDF, CANDELS, and now the Frontier Fields) and VISTA (e.g. UltraVISTA and VIDEO) it is now possible to observationally identify and characterise galaxies well within the first billion years of the Universe’s history over a wide range of luminosities and environments. More recently, ALMA has also begun obtaining observations of these sources revealing the nature of the ISM in these nascent galaxies and throwing up challenges for galaxy formation modelling. In the near future the first direct detections of the Epoch of Reionization by LOFAR and other ongoing large experiments are expected. Numerical simulations and detailed modelling of the reionization epoch are crucial for reliable interpretation of those detections, for deriving the numbers, clustering and properties of the reionization sources and understand the structure formation at high-z.

This session will review the current status of both the theoretical and observational progress in our understanding of distant galaxies and their role in the evolution of the Universe.