This e-book discusses and contributes to the further development of the theory of attractive quality, often referred to as the Kano model. The theory of attractive quality was introduced to the Western world through the 1984 paper entitled "Attractive Quality and Must-Be Quality" by Professor Noriaki Kano and his colleagues (Kano et al., 1984). This e-book aims to encourage research on the theory of attractive quality to enter a new phase of development. It especially calls for empirical investigations into the use and application of the Kano model and theoretical development of the theory of attractive quality. This e-book spans a wide range of topics, from further extensions of the Kano methodology and new approaches to the classification of quality attributes, to lifecycles of quality attributes and the theory of attractive quality.