"Over the past decade, cosmology, the study of the origin and evolution of the Universe and structure within it, has evolved into a precision science. While we have learned much about the evolution and history of the Universe, many of the most pressing questions remain unanswered, such as: Why is the Universe accelerating ? What is dark matter ? Does General Relativity correctly describe the Universe as a whole ? How did the Universe begin, and what is the origin of structure in the Universe ? The overarching goal of the proposed research is to make progress on these fronts through studies of the large-scale structure of the Universe. In particular, the research will attempt to probe our theory of gravity, and unravel the nature and origin of the initial seed fluctuations out of which all structure in the Universe formed. Beyond these two science goals, the proposed research includes new ways of measuring weak gravitational lensing, which is the most promising tool to study the ""dark"" ingredients of the cosmos that do not interact with light (such as dark matter and neutrinos). These research goals will be pursued on all three fronts of numerical simulations, analytical modeling, and confrontation with data. With its significant investment in cosmology space missions such as Planck and Euclid, as well as ground-based surveys, Europe is poised to assume a leadership role in experimental and observational cosmology. The proposed research will make significant contributions towards maximizing the science output of these experiments and thus contribute to European scientific excellence."