"Entertainment Weekly" gave "The Ghost Map" an 'A' rating, saying, ""The Ghost Map" asks the reader to imagine a situation in which 'you could leave town for a weekend and come back to find 10 percent of your neighbors being wheeled down the street in death carts.' For inhabitants of mid-19th-century London, cholera rendered this apocalyptic vision a terrifying reality... Johnson traces the courageous and ultimately successful attempt by an anesthetist/scientist/sleuth named John Snow to discover how the disease was transmitted. And he does so in a way that brings to nightmarish, thought-provoking life a world in which a swift but very unpleasant death can be just a glass of water away."