Your book was about abandoned substations in New York City. What attracts you to crumbling buildings?

At first, there's a certain Indiana Jones aspect to the discovery. But after that initial awe wears off, what fascinates me most is that we as a society do not create buildings like this anymore, grand structures that are meant to last much longer than the architects. The hospitals in this book were created at a time when it was thought that architecture would help in the treatment of the mentally ill. The architects envisioned them as places of healing. It's kind of a romantic notion, but as an architect you want to think what you're creating is going to last forever and have a profound impact not only on the occupants but society as a whole.

In Oliver Sacks's introduction to your book, he points out that these facilities were called "asylums" because they were meant to be places of peace and refuge. Can you say more about how these buildings helped achieve that goal?

These places were created with noble intentions, and the architecture was certainly supposed to uplift people. The buildings were also sited in rural areas, which were supposed to encourage a healthier living style. But you can also look at the way the buildings were designed—they have these huge hallways where the patients were supposed to be social and hang out. It's also interesting to look at the arrangement of the buildings, the spaces in between them, because the idea was that the asylum was a whole community. The occupants would be on the grounds or on the farms keeping active. When you're strolling around the grounds, you can imagine what life was really like with thousands of people living and working there.

In the 1970s, there was a series of court cases that outlawed patient labor. How did those rulings affect the communal atmosphere you're describing?

The federal laws were passed for good reasons, but they also sucked a lot of the life out of these places. Obviously, the idea of work therapy borders on forced labor. But from what I learned, farming and building things did give the patients something to do in the absence of modern medical treatment. It took their minds off their troubles, and many of these people did get better. Part of it, too, was this notion of self-sufficiency. Since the hospitals were located in remote areas, the people needed to have farms and dairies where they could produce their own food, workshops where they could make everything onsite. There was a sort of utopian ideal behind these places, even if they later became something very different.

Some of your most striking photos show jumbled collections of toothbrushes and bowling shoes—everyday objects that were left behind. How did you happen to stumble upon these things?

I had to dig pretty deep to find some of those shots. In some cases, one of the workers would be showing me around and get a sense of what I wanted and lead me to rooms that still had artifacts of everyday life in them. By the time I got to most of the buildings, the rooms were empty or trashed or in such bad condition that they didn't yield a time-capsule-like photograph. So when I did find something like that, it was a goldmine. These things trigger emotions—they begin to describe not only a way of life in one of these institutions but the fact that there were thousands of people living there.