Several old and well-known viruses, such as those causing anthrax and smallpox, form a separate threat. Recent events seem to indicate that there is a genuine possibility of these being used as weapons of terror or even mass destruction. For this reason, large-scale production of smallpox vaccine has recommenced – whereas everyone had been convinced that it would never again be necessary. The danger of smallpox seemed to have been eliminated for good, since – as everyone thought – the smallpox virus had been purged from the face of the earth.

The complete eradication of viruses is probably an illusion, says Goudsmit. It is also debatable whether or not we actually want this to occur, whether we can continue to exist without viruses. In evolutionary terms, there is an ancient, enigmatic symbiosis between the human race and viruses, in view of the fact that the human genome consists substantially of virus DNA.

Viruses are made of common biological materials – proteins and DNA or RNA. But this is where every similarity with normal biological organisms stops. Viruses defy our familiar conceptualisation of life. Are they super-primitive or, in contrast, super-specialised? Perhaps both at the same time. They form an almost surrealistic phenomenon: they are not bacteria, plants, or animals. Familiar concepts such as organism, life, and death simply do not apply to this category.

But what exactly are they? Whatever they may be, they are certainly survivors. Researchers are now managing to generate a better picture of their astonishing powers of survival and adaptation. Jaap Goudsmit is well versed in this subject matter, and presents the very latest insights in a clear and well-organised fashion. Here, reality surpasses every fiction.