Selection is crucial decision making step in every field, be it a student learning system or a critical mission system. Multiple aspects have to be considered in order to make decisions precise and effective. Analytic Hierarchy Process (AHP) is the multi criteria decision analysis methodology. It assists the experts by providing interface to make comparisons among factors and alternatives. It is the kind of automating the selection process. The role of the paper is to review the studies related to AHP, conducted so far. The aim is to understand the proposal of applications in several areas.