I enjoyed most of the book, but I hated the concluding chapter. I would have preferred it if he had stuck to his subject rather than stringing together a series of personal opinions. The discussion of the relative risks of a nuclear holocaust versus bio-terrorism via a genetically engineered virus seemed forced. Does it really matter? The author somehow managed to work in references to both the Iranian nuclear policy and intelligent design in a book about cholera in the nineteenth century. Was there an editor?