“I came in to find the window on the floor and a 1,200-page manuscript all over the place,” said Mr. Janssen, director for academic and library marketing at Macmillan.

The 21st floor, which was added in 1905, three years after the rest was completed, can be reached only by taking a second elevator from the 20th floor. Though he loves his office, he said it could be a lonely place.

“You don’t get a lot of people walking by,” Mr. Janssen said. He compares it to being in a situation comedy: “Guest stars come by every now and then.”

On the 20th floor, windows are placed much higher up, the bottoms nearly at chest height. “I have an incredible view,” said Charles Bozian, Macmillan’s vice president for finance and administration. “But not unless I stand up.”

The small bathrooms alternate by floor, men on even, women on odd. “And the bathrooms are not very nice, either,” said Alison Lazarus, the president of Macmillan’s sales division. When important guests visit, she has them use the spacious bathroom on the 18th floor, by far the building’s best, offering a view all the way to New Jersey.

Because the building is narrow, it is flooded with light. Most employees have windows — big windows, which is a plus for the most part.

John J. Murphy III, director of publicity for St. Martin’s, remembers when he bought new glasses and then came into work. “I was sitting at my desk, and everyone kept coming in and looking at me oddly,” Mr. Murphy said. He then realized that because of all the light in the building, his tinted lenses never turned clear. “I looked like some Greek shipping magnate or shady drug dealer sitting here at my desk,” he said.