Some books/resources related to "Mole People"
Margaret Morton 'The Tunnel: The Underground Homeless Of New York City' (Yale University Press, 1996) [Photo book]
Jennifer Toth 'The Mole People: Life In The Tunnels Beneath New York City' (Chicago Review Press, 1993)
A vaguely interesting side-note, from Alex Burns as he wrote about the 1980s/1990s:
"Some cultural analysts saw the 'Mole People' as an alternative society model, a critique of liberal progress doctrines. Douglas Rushkoff's 'Cyberia: Life In The Trenches Of Cyberspace' (Harper SanFrancisco, 1994) included the 'Mole People' in its description of fringe communities. 'Mole People' became a description of the lowest caste within emerging New Media industries."
-Alex Burns, from: http://old.disinfo.com/archive/pages/dossier/id350/pg1/