What is the main problem in the story of mankind by Hendrik Willem Van Loon?

There really isn't a specific problem. The Story of Mankind" by Hendrik Willem Van Loon is a tale of mankind's development from the nothingness of the origins of the planet through modern day science and technology. Written early in the 20th century, the information in the novel is clearly dated, but still manages to provide a base for young readers as to the origins of man. Engaging and entertaining, this book is a must read for any audience.