Book excerpt: Contract is not only a spirit and a concept, but also a system and a method. As a spirit and a concept, it is very inclusive; as a system and a method, it is very practical. Contract is a theory with a long history and fruitful practice. The reform of administrative law starts with the contract. The author is honored to be one of the first scholars in mainland China to introduce the concept and basic system of civil contracts into administrative law. Although mainland China has not yet established the legality of administrative contracts through the legislative method of administrative procedure law, the research and promotion of a group of scholars in mainland China, including the author, mainland China revised the Administrative Litigation Law at the 11th meeting of the Standing Committee of the 12th National People's Congress in 2014, and for the first time included administrative agreement disputes in the scope of administrative litigation. The Supreme People's Court Trial Committee also passed the judicial interpretation of the "Provisions of the Supreme People's Court on Several Issues Concerning the Trial of Administrative Agreement Cases" at the 1,781st meeting on November 12, 2019, which came into effect on January 1, 2020. The great progress of administrative contracts in administrative justice is inseparable from the efforts of the first batch of administrative contract pioneers in mainland China, including the author! It is also a great affirmation and praise, for which the author is deeply gratified!