What every well-designed home needs.

New York Times story.

No picture of the stairs, alas!

Seven years ago, when Nader Tehrani and Monica Ponce de Leon, partners at Office dA, an architecture firm in Boston, were asked to renovate a five-story town house in the Back Bay neighborhood, they faced a singular design challenge. The house belonged to Elmar Seibel, now 54, a dealer in rare books on art and architecture, and his wife, Azita Bina-Seibel, 46, a chef and restaurateur.

Mr. Seibel’s personal collection includes at least 40,000 books on Persian and Iranian culture. He keeps many in a warehouse, but perhaps 14,000 or 15,000 are at home.

There is a 1491 copy of a medical book written by Avicenna, the 11th-century philosopher and physician also known as Ibn Sina. A 17th-century eyewitness account of the coronation of a shah, written by Jean Chardin, a French jeweler, is inscribed to Jean-Baptiste Colbert, then the finance minister of France. A 19th-century cookbook has 4,000 handwritten recipes of dishes made for the shah’s court.

The collection began with the birth of the couple’s son, Kian, now 13. Mr. Seibel, a West German native, and Ms. Bina, born in Iran, wanted to give him something from his mother’s family’s cultural heritage. “The original idea was to create something for him — but it takes on a life of its own,” Mr. Seibel said. (Kian, who is fluent in Farsi, has not yet read any of the books in the collection. But he says he will, soon.)

Where, then, were the 14,000 books to go?

“What holds the house together is a vertical staircase that wraps itself around a tower of books that goes up three floors,” Mr. Tehrani said. (The family lives on the top three floors, while Ms. Bina’s mother, Aghdas Zoka-Bina, and a tenant occupy apartments on the first and ground-floor levels.) The stairway ends just below a skylight. “The tower of books appears to pierce the skylight, though it doesn’t in reality,” Mr. Tehrani said.

“The staircase is the ‘it’ factor,” he added. The books are easily accessible from the staircase, just four inches away. Some shelves are designed to hold books upright, while others are wide and shallow, so that manuscripts or magazines can be left there, in an offhand way — and they are. Many of the shelves are backed in translucent glass to let natural light shine through, and recessed lighting in the ceiling makes it possible to grab a book, settle onto any step and read in perfect light. Squinting is not required.

We just bought 80 surplus library bookcases.