The purpose of this book is to serve as an introduction to phenomenology as a philosophy arising from our everyday lives. This chapter, which marks the beginning of this introduction, outlines the overall structure of Husserl’s phenomenology, which is roughly divided into three levels. From Chaps.  2 to 11 , the topics of the individual chapters are assigned to these three levels, creating an overall picture (three-layered structure) of Husserl’s phenomenology. The first level is the realm of passive intersubjectivity, which arises from passivity prior to the formation of self-consciousness. The second level is the realm of active intersubjectivity, which arises from the activity associated with self-consciousness. The third level is the realm of interpersonal community (I-Thou relationship), which is free from egocentricity. In the rest of the book, the thematic outlines presented here for each chapter are explained in detail and developed into detailed and clear descriptions.