Local non-Gaussianity from inflation

The non-Gaussian distribution of primordial perturbations has the potential to reveal the physical processes at work in the very early universe. Local models provide a well-defined class of non-Gaussian distributions that arise naturally from the nonlinear evolution of density perturbations on super-Hubble scales starting from Gaussian field fluctuations during inflation. I describe the δ N formalism used to calculate the primordial density perturbation on large scales and then review several models for the origin of local primordial non-Gaussianity, including the curvaton, modulated reheating and ekpyrotic scenarios. I include an appendix with a table of sign conventions used in specific papers.