He was a pillar of the community, serving on local committees, donating prizes to the rugby club, organising charity collections. His patients thought the world of him: he was attentive, kind, never too busy to chat. Yet Dr Harold Frederick Shipman was also the most prolific serial killer the world has ever known, with between 200 and 300 victims. Quietly, for many years, the small, bespectacled GP was making unexpected house calls - and walking out leaving a dead body behind.

The murderous career of Dr Shipman only came to an end when police in Hyde, Greater Manchester, were called to investigate a forged will. Overnight, they found themselves embroiled in the biggest murder case in British history.

Substantially revised and updated since Shipman's suicide in prison, this is a compelling account of these monstrous crimes and of the man who committed them. The authors have had unparalleled access to friends, colleagues and patients. Their in-depth and authoritative investigation looks at how he killed, how he was able to get away with it for so long, and - most important of all - why.