This is well-paced book of recollections by a 56-year-old senior police officer, the former head of Scotland Yard's Obscene Publications Branch. The style is just short of British tabloid, factual without fuss. It imparts a sense of urgency that demands - as it holds - the reader's attention. Hames covers ground familiar to specialists involved in investigative work of this kind - police, social workers, health officials - but much of will be unfamiliar to the general public, and therein lies its value. The thesis to emerge is that it is not within the power of the State to control adult pornography. But the determination of governments to stop paedophiles transmitting child pornography is as strong as ever, Hames insists. The "Dirty Squad" changed its agenda over time, ultimately spending 90 per cent of its effort combating child abuse. That was no accident.