Jennifer Toth, The Mole People: Life in the Tunnels Beneath New York City, 1993.
Toth's study of life underground in New York is fascinating. Drawing from her work as a journalist, the work is largely anecdotal, describing her encounters with a large number of people who live beneath the surface. The anecdotes and character sketches are supplemented with statistics and interviews with officials, and together, the information draws a picture of a vast--and, in many cases, more caring--city underneath the official city.
Toth examines why people go underground, and deals with the truth behind the stereotypes of such people, and the limits of those truths. Her compassion for the people she describes is palpable. Though many suffer from the ravages of drug addiction and mental illness, she helps them tell their stories: this in turn lets Toth show the reader what different communities are like, how children are raised, the status of women, how authorities are attempting to help/deal with the underground dwellers, and more.
While the book could well stand to be laid out more clearly, it does give a comprehensive survey of what life looks like, and how it's organised, under the surface. Movingly and compassionately written, it's as hard a book to put down as it is to keep reading. I'm glad I read it.