The current expansion of the Universe is now firmly established through observations of Supernova, Large Scale Structure and the Cosmic Microwave Background. However, what the nature of dark energy is remains a mystery. On the other hand, a closer look at the possible mechanisms that can be accelerating the universe today, shows that one can exploit the machinery developed to understand inflation to understand dark energy. In this talk, I will demonstrate how one can develop new theoretical tools to unveil the nature of dark energy and show what constraints we currently have on the nature of dark energy and how future constraints may unveil the nature of dark energy.