We review the development of the concepts which form the basis for a theory of large scale statistical thermodynamics of granular flow. While the first law (the balance of large scale energy) has been known for over 15 years, the second law (the balance of large scale entropy) has been introduced only recently. The time delay is traced back to the fact that the conceptual distinction between large scale energy and large scale temperature has not been easily identified. We also discuss how large scale statistical thermodynamics may be used to yield concrete results of a general nature in the theory of granular flow.