The Modern Inflationary Cosmology collaboration aims to drive forward our understanding of the theoretical underpinnings and observational consequences of early universe cosmology. It will undertake a major upgrade of the theory of primordial interactions (non-Gaussianity) and its observational constraints, taking into account strongly non-linear effects intrinsic to quantum field theory and the evolution of structure in the universe. The collaboration will extend our control of initial conditions for inflation, using mathematical features of 3-manifolds along with the latest numerical relativity techniques. It will develop the underlying theory of inflation, with control of quantum gravity effects. These efforts will expand our understanding of inflationary dynamics and meaningful constraints on its parameters, providing new insights into the density perturbations seeding structure in the universe. The collaboration includes J. Richard Bond at the Canadian Institute for Theoretical Astrophysics, Raphael Flauger at UCSD, Liam McAllister at Cornell, Matias Zaldarriaga at the Institute for Advanced Study, and Renata Kallosh, Andrei Linde, Leonardo Senatore, and Eva Silverstein at Stanford who serves as collaboration director.