Ghost Map Discussion Guide
Includes summary and discussion questions

Steven Johnson's Website

UCLA Department of
Epidemiology John Snow site

Michigan State University John Snow Archive and Research Companion

Also available as a hardcover, an audiobook, and an ebook

It is the summer of 1854. Cholera has seized London with unprecedented intensity. A metropolis of more than 2 million people, London is just emerging as a one of the first modern cities in the world. But lacking the infrastructure necessary to support its dense population - garbage removal, clean water, sewers - the city has become the perfect breeding ground for a terrifying disease no one knows how to cure.

As their neighbors begin dying, two men are spurred to action: the Reverend Henry Whitehead, whose faith in a benevolent God is shaken by the seemingly random nature of the victims, and Dr. John Snow, whose ideas about contagion have been dismissed by the scientific community, but who is convinced that he knows how the disease is being transmitted. In a riveting day-by-day account, The Ghost Map chronicles the outbreak’s spread and the desperate efforts to put an end to the epidemic - and solve the most pressing medical riddle of the age.

The Ghost Map is the chilling story of urban terror, but it is also a story of how scientific understanding can advance in the most hostile of environments. In a triumph of dynamic, multidisciplinary thinking, Steven Johnson examines the epidemic from the microbial level to the human level to the urban level. Brilliantly illuminating the intertwined histories of the spread of disease, the rise of cities, and the nature of scientific inquiry, Johnson presents both vivid history and a powerful, provocative explanation of how it has shaped the world we live in.

Steven Johnson is the author of the national bestsellers Everything Bad is Good For You and Mind Wide Open as well as Emergence and Interface Culture. He is a Distinguished Writer In Residence at New York University’s Department of Journalism and the founder of several influential websites, including FEED, Plastic, and, currently, He lives in Brooklyn with his wife and three sons.

That is how it began...

"The Most Important Fact of the Last 200 Years"

A Pattern Becomes Visible...

Amateurism, Cross-Disciplinary Thinking, Local Knowledge, and the Future of Cities

Cholera Came Back: 1850s London and Today's Megacities

The Map Itself: A Work of Persuasion, A Neighborhood Representing Itself

How to Catch and Cure Cholera

Dr. John Snow: One of the Great Minds of Victorian Science

“By turns a medical thriller, detective story and paean to city life, Johnson's account of the outbreak and its modern implications is a true page turner.”
- The Washington Post

“Johnson brings to nightmarish, thought-provoking life a world in which a swift but very unpleasant death can be just a glass of water away.”
- Entertainment Weekly
(An Entertainment Weekly Best Book of the Year)

“"There's a great story here...and Johnson recounts it well.... His book is a formidable gathering of small facts and big ideas, and the narrative portions are particularly strong, informed by real empathy for both his named and his nameless characters.... Fascinating.”
- David Quammen, The New York Times Book Review
(A New York Times Notable Book)

“Johnson adds a new and welcome element - old-fashioned storytelling flair… - to his fractal, multi-faceted method of unraveling the scientific mysteries of everyday life.”
- Los Angeles Times Book Review

“Steven Johnson gives us history at its best: colorful, connected and compelling. At the core is a medical mystery, or what today would be called an epidemiological detective story.... A masterpiece of historical writing.”
- Seattle Times

“Steven Johnson tells the tale with verve, spicing his narrative with scenes of Dickensian squalor and the vibrant street life surrounding that squalor. But in Johnson's hands, Ghost Map morphs into something more than mere history…Readers will recognize a reworking of [Johnson’s] favorite themes: the interface of culture and technology; the phenomenon of emergence (the bottom-up organization of small interconnected elements into more complex systems); and always, like a constant bass line in Johnson's extended riff, the theme of urbanism - the metropolis as a glorious culmination of emergence, technology and culture.”
- San Diego Union-Tribune

“Unputdownable.... Marvelous...just as was Dava Sobel's Longitude. Yet The Ghost Map is a far more ambitious and compelling work.... Wonderful. ”
- The Wall Street Journal

“This is more than a great medical detective story. It's the triumph of reason and evidence over superstition and theory, and Johnson tells it in loving detail.”
- Chicago Tribune

“In this tightly written page-turner, Johnson uses his considerable skill to craft a story of suffering, perseverance and redemption that echoes to the present day. Johnson weaves in overlapping ideas about the growth of civilization, the organization of cities, and evolution to thrilling effect. From Snow's discovery of patient zero to Johnson's compelling argument for and celebration of cities, this makes for an illuminating and satisfying read.”
- Publishers Weekly (starred review)

“[Johnson] has latched onto a truly compelling story, and he calls in the voices of Charles Dickens, Samuel Pepys, George Eliot, Jane Jacobs and Stephen Jay Gould to help tell it. They make a lively chorus. In 1854, London was the densest settlement on the planet, with 2.5 million souls crammed into 30 square miles and an infrastructure awash in sewage. Enter Vibrio cholerae…We know these details thanks to the bravery and intellectual independence of two men. Dr. John Snow bucked the medical establishment's certitude that cholera was transmitted via foul air. And the Rev. Henry Whitehead, an Anglican curate, went out into the teeth of the epidemic to comfort his parishioners and puzzle over the strange pattern of their deaths. Johnson gives us a dashing sense of his two iconoclasts groping for explanations and gradually becoming allies. Johnson describes Snow as a ‘consilient thinker,’ an E.O. Wilson term for those who nimbly cross disciplines and create connections. Our author clearly aspires to be the same.”
- Cleveland Plain Dealer

“Johnson builds suspense in detailing the intersecting quests of Dr. John Snow and young clergyman Henry Whitehead to find the source of the illness as it strikes the city's population. Johnson is interested not only in how groundbreaking theories are developed but also in how faulty ideas can persist. Ghost Map also contains surprising historical nuggets.”
- USA Today

“In addition to telling the story of the outbreak, Johnson offers mini-lessons on related topics: how cholera kills, how Victorian London dealt with its messes, how and why people cling to false theories. Lively and educative.”
- Kirkus Reviews