Illness is a struggle to survive for both host and microbe, but we almost never hear the germ's side of the story. In this follow-up to Plague's Progress, Karlen tells the life story of the germ Borrelia burgdorferi, the cause of Lyme disease. He takes readers through its ancestry, environment, life cycle and encounters with various other species, including us, reminding us in the process that the human drama is not the only compelling one in nature. Interwoven throughout are meditations on the nature of sickness and health, and lucid explanations of molecular biology.