This book will try to contribute to help people have more knowledge about a special transitional period, about a very special hinge period in every aspect of the history of Vietnam, Cambodia, Laos during the colonial period, and more broadly, to the history of colonial France. it was the moment of establishing a rational and efficient mining apparatus in Indochina after the military conquest ended (which was later replaced by pacification) and before the construction mission began. Writing this interesting history, based on a study of the archives of the Colonial Ministry and the archives of the Indochinese Government transferred to archives in France, Amaury Lorin sheds light on a period when Indochina was a colony of France that has not been thoroughly understood by far. A period of existence interwoven with dark, light-emitting spaces, especially striking a complex character with an incredible will and a unique career.