As he and wife Linda were house hunting, Keith Mock recalls, a real estate agent seemed convinced that repeated mention of the fact that renowned architect Louis Kahn had lived in a particular Philadelphia home would get it sold.

The Mocks bought the house, all right - but because it was on Clinton Street in Washington Square West.

"We wanted to live on this wonderful street because it is only two blocks long and it is private and has a 19th-century quality, not because of Kahn," Keith Mock says. "There is no through traffic, and the street combines single-family houses and apartments and is close to everything."

Mock is a principal at the architectural firm Ballinger and is copresident of the local chapter of the American Institute of Architects. Linda Mock is an interior designer and volunteers at the gardens at Independence National Historical Park.

The couple and their three college-age children are proud of walking everywhere from their new home, an improvement over their previous commute from suburbia.

"I'll bet he wanted to live here for the same reason we do," Keith says of Kahn. "His office was also walking distance from here."

Kahn lived in the house about 20 years, until his death in 1974. His wife, Esther, continued to live there and served as a community leader until her death in 1993.

Though you can't exactly hear Kahn utter his famous question, "What does a house want to be?," his history in the 19th-century structure is everywhere.

Upon entering the four-story building - its small footprint is just 15 feet wide and 115 feet deep - a visitor finds herself in a small white foyer with tall white cabinet doors set to one side.

Kahn created the foyer by converting a closet, Keith says.

"Before that," Linda says, "you walked straight into the living room from the street.

"The living room/dining room combination used to be a series of rooms, converted to one long room," she says. Polished, random-width heart-pine floors make the room look even longer.

The Mocks reversed the customary placement of the living and dining areas so their oak table and chairs are set beside large 12-pane front windows.

The larger living room, complete with sofa, TV, chairs, and coffee table, inhabits the space toward the back, leading to the kitchen.

Both areas are next to fireplaces.

"There were fireplaces in every room," Linda says. They were the main sources of warmth until Kahn installed a heating and air-conditioning system.

The kitchen had once been a separate shed, 8 feet wide and 18 feet long, before Kahn moved in and redesigned it, attaching it to the main building.

"I looked at the kitchen and immediately said, 'It has to go,' " says Linda, who explains that she loves to cook. "Kahn's family apparently didn't cook."

Still, the master's basic design was worthwhile.

"Our kitchen redesign was an attempt to reinterpret and modernize the original Kahn design," Keith says. That included outfitting it with a six-burner gas stove, a grained-wood-covered refrigerator, and a dishwasher.

The room includes a huge rectangular window Kahn designed, which is where the Mocks have placed a counter and chairs for informal meals.

Keith thinks there's a connection between the kitchen window's design and "Kahn's careful attention to bringing natural light through interesting geometric-shaped windows. Many of his buildings use squares, circles, and three-sided shapes."

A steep stairway leads up to three floors of bedrooms. Each landing opens out to a bedroom and bath.

"I think this may have been the basis of Kahn's design of the Richards Building at Penn, with a room opening up at each landing on a staircase," Keith says.

As Kahn and others did before them, the Mocks are "taking their turn making the house their own.

"It is a participatory event shared by all homeowners," he says. "The next owner can continue to be influenced by this wonderful house on Clinton Street."