'For if once a man indulges himself in murder, very soon he comes to think little of robbing; and from robbing he comes next to drinking and Sabbath-breaking, and from that to incivility and procrastination'Thomas De Quincey's three essays 'On Murder Considered as One of the Fine Arts' centre on the notorious career of the murderer John Williams, who in 1811 brutally killed seven people in London'...