The Northern Warlords were one of the most influential warlords in northern China in the late 19th and early 20th centuries. There were many books about the Northern Warlords, some of which were more famous, such as The History of the Northern Warlords, The Sequel to the History of the Northern Warlords, and The New History of the Northern Warlords. " The History of the Northern Warlords " was a book that systematically introduced the history of the Northern Warlords, including the formation, development, rule, and extinction of the Northern Warlords. The book is easy to understand and suitable for beginners. " The Sequel to the History of the Northern Warlords " was the continuation of " The History of the Northern Warlords ". It continued to introduce the history of the Northern Warlords. The content of the book was relatively rich. It gave a deeper understanding of the history of the Northern Warlords. The New History of the Northern Warlords was a comprehensive book on the history of the Northern Warlords, including the history, politics, economy, culture, and many other aspects of the Northern Warlords. The book systematically introduced the history of the Northern Warlords, suitable for readers who had a deeper understanding of the history of the Northern Warlords. It should be noted that the history of the Northern Warlords is very complicated. The above three books are only a part of it. The readers can choose the books that suit their needs and interests.