In 1991, as India was being injected with the hormones of market capitalism, a group of Tamil labourers settled on a slice of brushland near Mumbai's international airport.
Called Annawadi, their slum sat 200 yards off the main airport road.
As the country boomed and blushed at the mention of the millions still living in squalor, a concrete wall went up to hide the settlement from passing cars.
The wall was covered with ads for Italianate tiles; the slogan read: "Beautiful Forever Beautiful Forever Beautiful Forever."
Katherine Boo, a staff writer at The New Yorker, spent more than three years behind the concrete wall. As the economy grew, governance decayed and Annawadians lusted after "one of the life-changing miracles that were said to happen in the New India", she recorded the lives of the residents, eventually distilling this into her first book. The result is an intricate account of how people respond to hardship, promise and the whimsy and caprice of a hollowed-out state.
Deploying spare, unadorned prose, Boo throws the slum-dwellers into such sharp relief that, reading the book, one has the sense of seeing them at first hand.
This is a trick of the writing that succeeds because of Boo's style - the word "I" is absent from the narrative - and focus on a clutch of Annawadi's residents.
The combination - the invisible reporter, the disciplined gaze - marks this book out from the recent crop of non-fiction about those on the margins of modern India. Like Boo, Sonia Faleiro in Beautiful Thing and Aman Sethi in the forthcoming A Free Man draw fine portraits of forgotten lives (a bar dancer in Beautiful Thing, a daily-wage worker in A Free Man).
Unlike her, they appear in the narrative, visible middlemen between reader and subject. By absenting herself, Boo endows her writing with an uncommon immediacy, bringing to life characters such as Sunil, a 12-year-old scavenger concerned that lack of food stunts growth.
"To kick-start his system, he saw he'd have to become a better scavenger. This entailed not dwelling on the obvious: that his profession could wreck a body in a very short time. Scrapes from dumpster-diving ... became infected. Where skin broke, maggots got in. Lice colonised hair, gangrene inched up fingers, calves swelled into tree trunks," writes Boo. Better conveying in a few sentences the trials of life at the bottom of the ladder than a stack of economic tomes.