Hypochondriasis is the late 20th century's most serious disease, laying waste whole market towns (particularly in the south west of England, for some reason) and Dalrymple believes it is urgent we find a cure. Indeed he thinks he has found it. But, like the proper doctor he is, he takes a careful history before proceeding to the diagnosis.
We live in a society in which a visit to the doctor is the nearest many people come to a social engagement. (The book is riddled with aphorisms such as this.) But, since we are healthier now than at any time in history, we have to find reasons to attend the surgery. So we stir ourselves up into a "permanent effervescence of publicly funded panic" over listeria in the pate, hormones in the water and power lines over our heads.
There is nothing new about health scares. What is new is the "unique inappropriateness and redundancy of the anxieties suffered by millions", says the good doctor. "They frighten themselves with trifles ... to avoid contemplation of the void at the heart of their existence."
Well, up to a point. Dalrymple's belief that man is in an "existential funk" - and a symptom of this is his obsession with health - is a good point, elegantly made. But there is another side to this story. A major problem with health scares today is that, thanks to scientific advance, we are getting the information so much earlier that there is time to worry about what action to take before there is any good evidence on which to take it.
Take the mother of all health scares, the fear that BSE-infected beef can transmit CJD to humans. We are now almost two years into it and we still don't know the degree of risk, the extent of any likely epidemic or even if there is, definitely, a causal link at all. The reason is that never before have we spotted a new disease (if that is what it is) so early in its course. Necessarily that means the period of uncertainty, while science determines what is going on, is extended. We cannot go and look, we can only wait and see.
While we wait, how can we curb our fear? By remembering how much worse things used to be. Like most doctors, Dalrymple likes nothing better than a good medical horror story. Worried about listeria in the pate? Pshaw. Dalrymple has the answer: a stomach-heaving account of Philip II of Spain's death, writhing in pain in his own ordure as his body disintegrated, followed by an equally harrowing account of the novelist Fanny Burney's mastectomy - without anaesthetic.
The best medicine is stoicism, the finest therapy humility and fortitude. As Dalrymple says, all three are in short supply. Yet death is coming to us all, sooner or later, and there can be no serenity in the face of it without these three.