Following advances in industry, rubber became a valuable commodity - at first, the Congolese thought this new trade would bring prosperity to their country. Instead, what ensued was murderous and exploitative barbarity of a scale never seen in Africa. Between 1890 and 1910, the Belgian forces occupying the Congo in Africa perpetrated horrific atrocities against the indigenous population.

King Leopold II had brought Congo directly under his control. He permitted his soldiers to commit mass murder and enslavement, rapes, mass amputations, beatings and degradation of the population. Millions of Congolese died in the midst of this atrocious misrule. Belgium however profited enormously, and Leopold II spent some of his revenues from rubber sales on grandiose public building projects.

Edmund Dene Morel was a British politician and campaigner who worked for years investigating and publicizing the brutality of Belgian rule in the Congo. He was appalled when Britain stood idly by as Leopold II's tyranny ensued. Morel first published this book in 1906, while this reprint is derived from an updated edition of 1919; by this time the king had died, having finally been forced to surrender his control of the colony to the government of Belgium.