THE WAY Athos Pratesi figures it, about half the important people in Italy were procreated between his sheets.

He's probably not far off, since the Pratesi family makes and sells sheets and pillowcases to the well-heeled of the world. Mostly in Italy, of course, where he is from, but literally everywhere.

When the Kennedys were in the White House, Pratesi sheets in cotton or cotton polyester were used. The Vatican buys the all-cotton classical variety. So do the royal families of Belgium, Monaco and Belgium. Frank Sinatra is a customer, as are the Agnellis, the Rockefellers and the Peugots. Sinatra picks out his sheets in the Pratesi shop in Beverly Hills. Kenny Rogers just acquired some silk satin sheets and a down comforter for $5,000 for his new mansion at a benefit auction.

That hardly makes Rogers the biggest spender among Pratesi customers. A "kingly Arab family," Pratesi won't say exactly who, outfitted its 18-bedroom royal yacht, including curtains and blankets, for $600,000.

It is not all that difficult to spend that much when you consider that the twin-size basic, all-cotton embroidered sheet starts at $124, and the same size in pure linen sells for $250. A silk sheet in king-size -- that's the most popular size in silk -- costs $580, and in silk satin about $840. (Because of high import duties, cotton blends cost the same as pure cotton.)

"One spends one-third of one's life in bed, so we want to make that time as luxurious and pleasant as possible," Pratesi recently said through an interpreter. He was in Washington to consider opening a shop, similar to the ones he has in Beverly Hills, Palm Beach and Bal Harbour.His products can be ordered from Neiman Marcus here.

"When you go to sleetp to relax and to absolutely rest, linen is probably the most restful and the coolest," says Pratesi."Going to bed in silk sheets is almost like having amother presence near. You feel close to your skin. It is like sleeping with somebody else." He says he personally uses silk and cotton during the winter, but from June to September only linen: "There is no fiber which is as cool and pleasant as linen."

Pratesi recommends washing silk, even machine-washing silk on a gentle cycle. Five years ago his company started making a silk that is easily washable, "it's only fault being that it has to be pressed when it is damp to give the best performance." He smiles and adds quickly, "I wouldn't wnt to sleep on a sheet that has been dry-cleaned."

But unlike some who travel with their own sheets, Pratesi is willing to put up with whatever he finds on the bed when he travels in the United States. "I make so many stops it wouldn't really be practical," he says. The one respite on his travels, he says, is the Fairmont Hotel in Dallas which has quality sheets and linen towels.

His personal tastes run to the classic styles and colors. "Remember that Egyptian mummies were found wrapped in white linen sheets," he says. But for his customers, there is a wide color range both in solids and prints.

"We are going through difficult and violent periods in Italy and as a reaction people are buying almost exclusively white and pink as restful colors," he says. "Summer seems to be the time people prefer strong colors like saffron yellow, orange, blues and greens."

They also carry six different shades of beige and black, which he sells to some jet-set families he will not name. One customer, he says, ordered a huge quantity of black sheets in the Madison Avenue shop. They had to be unpatterned, she said, but if enbroidered, they had to be black on black. She explained to Pratesi, "I have black walls and black carpets and now I want black sheets. I want the total absence of color for complete rest. I don't want to be distracted by anything." Black, he says, is also a favorite color for rich Mexicans.

Athos Pratesi is the third generation in a family business started in 1896 in a small town near Florence, close to where Leonardo da Vinci was born. All his company's products are made there in a modern factory designed by Nervi (who designed the Verrazano bridge) and Michelucci (who is known for his ascetic churches) set among the olive trees and cypresses.

Twelve members of the family are now in the business, including a brother who goes to Karthoum in Sudan once a year to buy the best cotton which is then woven in Italy. (Pratesi uses 70 percent of the quality cotton Karthoum produces.) Pratesi uses Italian and Chinese silk. "Chinese is high quality but the Italian is more flexible and makes a softer cloth," he says. They use as much Italian silk as they can get.

Pratesi recently added a line of leisure robes, all very classic in shape and mostly in cotton terry cloth. "Peope are spending 20 to 30 percent more time at home than they did even just three to four years ago," says Pratesi. He says he has studied electricity usage in the home to come up with these figures. The robes are cut quite lose, with all seams bound and finished on the inside.

His four children are ready to step into the business -- so are lots of companies who have offered mergers and takeovers, but he has turned down outsiders.

For himself, learning from the bottom, knowing every single phase of the production is essential in being a good capa , he says. There are 200 people in the factory and they re artists," he says. "When you are dealing with artists you cannot give them orders, you must reason. My fiercest critics are the workers. I am afraid of their judgment because they are very competent."

Soon there will even be wallpapers -- total textile furnishings, as he calls it. "The next few years will be the years of being home -- people need to be home more. Outside is dangerous to begin with, also it is too noisy," he says. "It is not so pleasant outside to people so they go back to their home and invite friends. Not for loud parties but quiet occasions where people discuss things. You invite someone and you spend your evenings talking."

And perhaps for some -- very expensive pillow talk.