The greatest villain who ever stood trial at the Old Bailey, as Charles Dickens described him, William Palmer was convicted in 1856 of murdering his best friend, but was suspected of poisoning more than a dozen other people, including his wife and children. He was a new kind of murderer: respectable, middle class, and consequently more terrifying, Britain's most infamous figure until Jack the Ripper. 'The Poisoner' takes the reader into the very psyche...