Methodology is the study of how one can reach objective truth. In fact, the English word method is derived from the Greek word meta (following) and hodos (the way). Thus, “method” implies that in order to attain some purpose, one should follow a certain way. From the time of ancient Greece until today, many philosophers developed their own unique methodologies to find the truth. Here we will first take up some representative traditional methodologies, and then present the methodology of Unification Thought, that is Unification methodology. Finally, we will examine some of the traditional methodologies from the standpoint of Unification Thought. What I should add here is that it is not my intention to introduce the traditional methodologies in all of their academic detail. I will only introduce certain main points of those methodologies in order to clarify that Unification methodology can solve their problems.