This is high drama played out on a very small stage: a microbe's life seen from its own point of view. The bacterium Borrelia burgdorferi (Bb for short) is a tiny, pale spiral, invisible to the naked eye, yet no one could invent a life so ingenious, or one so tied to so many creatures' fates. We know Bb as the germ that causes Lyme disease, but that is just one recent chapter in its age-old struggle to survive. In this brilliant and original book, Arno Karlen takes readers on a fantastic journey through Bb's world--its ancestry and evolution, its day-to-day life, its perilous travels through ticks, mice, and deer, and, finally, its collision with humanity. Its life evokes the vast ecological web in which we and Bb are threads.

Bb is of special interest because it is one of a score of microbes that recently shifted to humans from other species, causing such epidemics as Lyme disease and AIDS. Like its microbial brethren, Bb entered our bodies because we invited it to, by changing our environment and behavior. Its history shows how germs, their hosts, and their shared environment all shape one another.

But Bb is fascinating in its own right, a distinctive member of bacteria's invisible kingdom. And its story is an homage to the researchers who discovered it, mapped its genes, and continue to explore it.

Imaginative, entertaining, and compelling, Biography of a Germ makes science pure pleasure.