Sublimely equipped to survive, to propagate, to conquer, the virus is neither really alive nor really dead. Its dimensions are measured in molecules. It attacks by dismantling its human targets cell by cell.

Level 4: Virus Hunters of the CDC is an intense, personal account of more than a quarter-century on the front lines - in the ultra high-tech "hot zone" lab that McCormick was instrumental in creating at the Centers for Disease Control headquarters in Atlanta, as well as in the most primitive places on the planet, where the local climate, terrain, and politics can kill just as surely as any disease.

Told in intimate detail by two of the world's best-known virologists - colleagues, collaborators, husband and wife - Level 4 is a journey across the world and into many strange new worlds: from the seductive beauty of equatorial Africa - a limitless reservoir of infection - to the confines of the all-but-invisible field of the electron microscope.

While other books have offered hot zones, sick monkeys, and grim statistics, Level 4 brings home from the world of the virus the human stories of those who lived, and those who died.