Using customer requirements and needs in the product development process has become a major subject in quality engineering. Many scholars have tried to develop systems that enable product developers and designers to consider customer requirements during the design process. Among them, Kansei Engineering (KE) is the first to consider customer feelings as input to the design process. KE is a Japanese word which doesn’t have an exact synonym in English but can be interpreted as sensibility, feeling, or aesthetics. KE was originated in Japan around 1970. Although applications of KE began from automotive industries, nowadays many other industries such as electric home appliance industry, office equipment industry and so on, have made extensive use of KE. There are six techniques for the implementation of KE concept: Category Classification, KE computer System, KE Modeling, Hybrid KE System, Virtual KE, and Collaborative KE. These techniques differ from each other in their approaches to apply KE in different development process situations in terms of information availability, complexity, and required performance. This paper presents a detailed critical review of the KE concept and a new classification based on computational and non computational approaches. It will also provide a review of the application of KE in different areas.