This textbook systematically addresses why and how Circular Economy should be developed and practiced by employing a Discussion and Research (D&R) teaching method. This method allows us to show the whole process of academic research, from formulating the key questions, to methodology design, and ultimately to conclusions and applications. In addition, the suggested class discussions and group homework provide good opportunities for participant cooperation and exchange. In this textbook, all chapters and sections are intended to answer specific scientific key or sub-key questions, while all chapters are also internally structured logically and systematically, from question to final conclusion. This textbook may help to boost student performance in science and research and was selected for inclusion in the 13th Five-Year planning teaching materials for regular higher education in China.