| At the end of inflation the universe would have been extremely cold and devoid of matter and radiation. On the other hand, we know that the early universe was hot and filled with matter and radiation. Therefore a crucial part of any inflationary scenario is to explain how the universe becomes repopulated with matter and radiation once inflation ends; a process called /reheating/. The initial stages of reheating are complicated by important non-perturbative effects which can drastically alter the outcome of the reheating process. This non-perturbative stage of reheating is called /preheating/ and it can have surprising cosmological consequences. In this talk, I will review the theory of reheating at the end of inflation and discuss preheating in some commonly studied models. Then I will discuss preheating in some not-so-commonly studied models. I will explain why preheating in these latter models could play a more important role during the reheating process than previously studied models. |