I moved house 15000 km recently and this was one of the few books that came along (the others are in storage). Most of the other ones are mentioned in other comments.
From the New Yorker review:
In 1649, after Oliver Cromwell and his army had taken King Charles I prisoner, they had to decide what to do with him. The easiest option, according to a contemporary, was assassination, "for which there were hands ready enough to be employed." Instead, a lawyer named John Cooke was given the brief to prosecute him. (Other lawyers left town to dodge the job.) At the time, there was no language for what Charles was charged with: as king, he was the law, so prosecuting him seemed a logical absurdity. Robertson, a lawyer involved in the prosecutions of Augusto Pinochet and Saddam Hussein, credits Cooke with helping to make those proceedings possible; he "made tyranny a crime." But Cooke himself was executed after the monarchy was restored. His heart and genitals were fed to stray dogs, and his head, at King Charles II's direction, was displayed at the entrance to Westminster Hall.