This article originally appeared in the February 2007 issue of Architectural Digest.

The highly articulate Lee F. Mindel has this to say about the way he and Peter L. Shelton, his longtime collaborator, approach the challenge of an apartment renovation: "The main thing is to identify the problem of a space and to reduce it to its purest essence. People get distracted when they buy an apartment. They go from falling in love to having buyer's remorse so quickly that they can't calm down and ask the most primal questions. What makes a place tick? What about its context is special? Is there some quality of the building that should be celebrated? How does the light work? What is it about the owner that brings specificity to his home? And, finally, what can we, as architects and designers, do to present the clients as the best they can be, given who they are?"

He pauses. "We ask and try to answer all these questions, then we throw them out the window and let intuition take over. Only then can something truly interesting happen."

For a pair of returning clients who had recently acquired a special apartment on Central Park West, Shelton and Mindel began by working down their list. There was a good deal that made this apartment tick. It was in a spirited Arts and Crafts building built by Henry Wilkinson in 1910. The unit Shelton and Mindel's clients chose, on the 12th floor, faced east and south over the park and had a corner view that was "on a scale," Mindel says, "that still made you feel connected to the magnificent city it inhabits." There was excellent light; there was a nice rhythm of windows with a glazed door that opened onto a balcony; the building retained a strong Arts and Crafts flavor.

At the same time, a lot was lacking. There were too many too-small rooms; while they were typical of the early 20th century, they felt claustrophobic in the early 21st. Radiators were exposed. Air-conditioning units were slapped into these precious park-facing windows, which began to feel rather too flimsy for the direction the apartment was heading in—freer and more modern, and as luminous as possible.

When Shelton and Mindel got to the point of letting their intuition float over this potentially beautiful space, it settled on what they saw as the apartment's key feature: its envelope, with its splendid view over the park and the spread of the city. The solution they came up with is simplicity incarnate, though naturally it was complicated to engineer and finesse: They devised a bay system to envelop the envelope.