Whereas 'King Leopold's Ghost' is a narrative history, it does cite many primary sources. The most important is 'Red Rubber' by E. D. Morel (now in the public domain). In addition Hochschild references numerous newspaper articles, letters, and written accounts. His interpretation is his own, but, that is every work of history and in many ways that's the least consequential element.

The story of the Congo in this period is a sad one and we see echoes of modern times in accounts of things that happened a century ago. "The children were drafted to the "camps of military instruction," to be made soldiers of in due course. The recruits were obtained by armed raids upon villages" - Red Rubber pg 24