What is the author's style in King Leopold's Ghost by Adam Hochschild?

The author became interested in the topic of colonization of the Congo while reading a book which quoted Mark Twain in a footnote. This initial spark of curiosity led to further investigation into the era considered in the text and, ultimately, led to the writing of the book. This personal interest, along with the author's expertise in writing, makes him highly qualified to write on the topic at hand.