THE NOISES.(residents of exclusive Manhattan co-op complain of neighbors' disruptive noises )

The Walters first began hearing the noises three years ago, at around eleven in the evening, as they were getting ready for bed. "Thuds, bangs," Richard Walter recalled recently. "Like someone whacking the floor with a two-by-four." This was joined, in the following nights, by another sound: "A buzzing. Like a loud bee noise. Zzzzzz. It was more or less constant, sometimes until two or three in the morning." The noises seemed to be coming from the apartment directly overhead and were as hard to account for as they were to sleep through. Night after night, the Walters lay awake, wondering and seething.

Richard Walter, who is eighty-one, and his wife, Linda, who is ...