The Cobra Event is the story of a secret counter-terror operation.  It is set in motion 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, blood is pouring out of her nose, and she has begun a hideous process of self-cannibalization.  Soon, other gruesome deaths of a similar nature have been discovered, and the Centers for Disease Control in Atlanta sends a forensic 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 and their use by civilian and military terrorists.  "The creation of advanced biological weapons using methods of genetic engineering and biotechnology is sometimes known as 'black biology,'" Richard Preston writes.  The extent to which the products of black biology are available nearly everywhere in the world is shocking.  Preston's sources for his 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.  The stories of what they have seen and what they expect to happen and how they plan to deal with it are chilling.     The Cobra Event is not science fiction.  It is a dramatic, heart-stopping account of a very real threat, told with the skill and authority that made Richard Preston's The Hot Zone an internationally acclaimed bestseller.