Who is Jules Marchal from King Leopold's Ghost and what is their importance?

Jules Marchal was born c. 1925 in Belgium. His native language was Dutch, but he is also fluent in French and English. He married Paula, probably c. 1947, and they have remained married through the book's publication in 1998. In 1948 Marchal worked in the Congo, apparently for Belgian commercial interests. He remained working in the Congo until c. 1968, thus living in the Congo during the last years of Belgian colonial rule and the first years of independence. In c. 1970 Marchal began working for the Belgian Foreign Ministry, and in the early 1970s he was the Ambassador to several African nations. During that time he read by chance an article on the Congo which had a footnote indicating that during Leopold's reign the country had suffered some ten million deaths. Marchal was flabbergasted, and initially assumed the article was in error.