The Mole People: Life in the Tunnels Beneath New York City (PB) (1995)

Thousands of people live in the subway, railroad, and sewage tunnels that form the bowels of New York City and this book is about them, the so-called mole people. They live alone and in communities, in subway tunnels and below subway platforms and this fascinating study presents how and why people move underground, who they are, and what they have to say about their lives and the "topside" world they've left behind.