Probably because Preston has inadvertently created a new hybrid of fact and fiction. Author of the nonfiction best seller ““The Hot Zone,’’ he tosses lots of factual–and utterly terrifying–information on biological warfare and gene splicing into his novel. But unlike Michael Crichton, who works similar territory, Preston has isolated his reportage in separate chapters, so you never confuse fact and fantasy. And the facts–what happens to a victim of a viral bomb, or merely what happens at an autopsy–are so thoroughly frightening that Preston’s threadbare novel becomes a page turner. ““The Cobra Event’’ is wretchedly told but wonderfully readable.
