Primordial non-Gaussianity from different cosmological scenarios

We review recent results about the level of non-Gaussianity in the primordial density perturbations generated in various cosmological scenarios, spanning from the standard single-field models of slow-roll inflation to new alternative scenarios. Through a full calculation at second order in perturbation theory we provide all the tools necessary to determine the level of the primordial non-Gaussianity in the large-scale Cosmic Microwave Background (CMB) temperature anisotropies in any model of cosmological perturbations. In light of present and future CMB observations we stress the importance of non-Gaussianity as a key discriminator among competing cosmological scenarios.