The Cobra Event is the story of a secret counterterror operation. The story begins one spring morning in New York City when a seventeen-year-old student wakes up feeling vaguely ill. She seems to be coming down with a cold. Hours later she is having violent seizures and has begun a hideous process of self-cannibalization. She is soon dead. When other gruesome deaths of a similar nature are discovered, the Centers for Disease Control in Atlanta sends a pathologist, an expert in epidemiology, to investigate. What she finds precipitates a federal crisis.

The details of this story are fictional, but they are based on a scrupulously thorough inquiry into the history of biological weapons. Preston’s sources for this story include members of the FBI and the United States military, public health officials, intelligence officers in foreign governments, and scientists who have been involved in the development and testing of strategic bioweapons.

President Bill Clinton read The Cobra Event (which reportedly it kept him up all night), and was so alarmed that he ordered an intelligence analysis of the book. The book affected White House policy regarding bioterrorism, and helped encourage the president to order intensified spending and preparations for a bioterror event. It has been said that the government would not have been as prepared for the anthrax letter attacks in September and October, 2002, as it was, without the stimulus of The Cobra Event.

“This is truly scary stuff, and Preston has obviously done his homework. . . He’s one of the few voices in the wilderness about the threat of bioweapons and our vulnerability to them. If even part of what he describes in The Cobra Event is possible, and he swears it is, then he has done us all a favor.”
--The Denver Post

[A] contagious thriller. . . About twenty pages in, you’re reading about biological weapon tests in the South Pacific, and you start thinking about all the stuff you breathe in every day and how invisible it is and what a cinch it would be for some nutcase to turn your entire town into a Hot Zone , , , Don’t bother trying to comfort yourself with the idea that this is science fiction. . . . Most of the science in this novel is fact. Even the government’s response in The Cobra Event is patterned on an existing plan to combat biological terror . . . Just as The Hot Zone reminded us of our vulnerability to exotic, natural infections, Preston’s novel means to awaken us to the truly scary threat of germ warfare.. . .Preston convinces us that it can happen here.”
--The Miami Herald