Cancer's life is a recapitulation of the body's life, its existence a pathological mirror of our own. Susan Sontag warned against overburdening an illness with metaphors. But this is not a metaphor. Down to their innate molecular core, cancer cells are hyperactive, survival-endowed, scrappy, fecund, inventive copies of ourselves.

Probably the most important reason we are seeing more cancers than before is because the population is ageing overall. And cancer is an age-related disease.

This was yet another colonial fascination: to create the conditions of misery in a population, then subject it to social or medical experimentation.

I began wondering, can one really write a biography of an illness? But I found myself thinking of cancer as this character that has lived for 4,000 years, and I wanted to know what was its birth, what is its mind, its personality, its psyche?

I had seen cancer at a more cellular level as a researcher. The first time I entered the cancer ward, my first instinct was to withdraw from what was going on - the complexity, the death. It was a very bleak time.

Good physicians are rarely dispassionate. They agonize and self-doubt over patients.

Cancer's life is a recapitulation of the body's life, its existence a pathological mirror of our own. Susan Sontag warned against overburdening an illness with metaphors. But this is not a metaphor. Down to their innate molecular core, cancer cells are hyperactive, survival-endowed, scrappy, fecund, inventive copies of ourselves.