Shepherd’s first major case as a forensic pathologist was the Hungerford massacre in 1987. One of his tasks was to check that Michael Ryan was dead after he had shot himself. Fearful that Ryan had a bomb, police would not go near: “I was on my own in a classroom with the UK’s biggest mass murderer.”

In his long career, he has conducted more than 20,000 post-mortems, seeking to establish the cause of death in people who have died from illness, crime, massacre and mass disasters. It’s an emotionally challenging job, and he acknowledges it involves suspending “some aspects of our own humanity”. But he finds the unique mix of medical knowledge and detective work immensely stimulating and has never lost his sense of awe for the “remarkable mechanism” of the human body and “its beauty”.

According to Shepherd, “pathology tells its own story”, and he shows this brilliantly by taking the reader through the often gory details of the cases he has dealt with, including the Marchioness disaster and the killings of Rachel Nickell and Stephen Lawrence. Despite its impact on his personal life, his belief in the importance of his work and his love of solving “death’s puzzle” is undimmed: “As humans, we have a need to know. About specific deaths. About death in general.”

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