The "understory," narrator Jack Gorse explains early on, as he wanders the hidden Ramble in New York's Central Park, is made up of "the shrubs and vines, rather than the elms, oaks, and maples. ... The things that live at ground level are what hold the earth fast."

This observation in Pam Erens' debut novel, "The Understory," might serve as a gentle metaphor for Jack, an obsessive, 40-year-old loner and creature of habit who is as overlooked as the smaller details he takes into account. He tends to his narrative with the same ascetic precision that characterizes a daily regimen of waking at daybreak and beginning his stroll through the city.