Specimen Days by Michael Cunningham

Specimen Days is a 2005 novel by American writer Michael Cunningham. It contains three stories: one that takes place in the past, one in the present and one in the future. Each of the three stories depicts three central, semi-consistent character-types: a young boy, a man, and a woman. Walt Whitman's poetry is also a common thread in each of the three stories and the title is from Whitman's own prose works.

The same group of characters--a young boy, an older man, and a young woman--are present in each historical period of this genre-bending, haunting, and transformative ode to life in New York.