Introduction to the Blue Book

The Blue Book was an official document written by the U.S. Department of Foreign Affairs in the early 20th century that recorded and summarized the diplomatic relations and agreements between the United States and other countries. It was a comprehensive document containing political, economic, military, and cultural information between the United States and other countries. The Blue Book was often used as a reference document for American foreign policy and an important legal basis for the United States to establish diplomatic relations with other countries.