Dr. Thanapol Chadchaidee has selected to study the process of political change since 1932. He hadmade the case study of: 1) the late Dr. Pridi Banomyong (1900-1983), 2) the late Prime Minister Kukrit Pramoj (1911-1995), 3) the late Professor Dr. Chai-Anan Samudavanija (1944 -2018) and 4) former Prime Minister Chuan Leekpai (1938 to present). These are the key figures in this period. They have made decisive impact on the Thai political system in order to make it more democratic. Dr. Thanapol has explained their role in changing the nature of the Thai political process. Dr. Thanapol’s work is unique and original and perhaps the first of its kind in the academic field of Thailand.