Years ago, Adam Hochschild came across a reference to the "five to eight million lives" destroyed in the colonial exploitation of the Congo. Startled, he realised that this had been "one of the major killing grounds of modern times. Why were these deaths not mentioned in the standard litany of our century's horrors?" His corrective history makes sobering and gripping reading. In King Leopold of Belgium, who decided to buy himself an empire to compensate for his country's smallness, he portrays a villain of Shakespearian dimensions. Aided by Stanley (of "Mr Livingstone I Presume" fame) the king appropriated a section of central Africa the size of Western Europe as his personal territory. The appalling brutality that ensued, as Europeans plundered the country for rubber and ivory, is vividly captured by Hochschild. He manages to leaven the horror with touches of grotesque humour--for instance, when tricking tribal chiefs into signing away their land for bales of cloth, Stanley would, to impress his dupes, secrete a battery in his pocket with the wires in his palm, so that on shaking hands the chief "was greatly surprised to find his white brother so strong that he nearly knocked him off his feet". Hochschild has something of Simon Schama's gift for populist history; and among other things he provides astonishing background to Joseph Conrad's Congo-set masterpiece, Heart of Darkness. --Adam Roberts