If you've lived in a rowhouse, surely you have a special rowhouse memory:

Of conversing in code through the bedroom wall with your best friend next door.

Of a neighbor's daily practice of singing big-band tunes, loudly. (You often hummed along.)

Of the impromptu block party that migrated from marble steps to someone's patio, and lasted blissfully into the night.

Of cleaving a parking space from snow and defending it with your dining room set.

They are memories of a shoe-horned lifestyle that thrusts intimacy upon strangers and makes priceless commodities of privacy, air, light and space.

Baltimore is not the only metropolis where rowhouse living predominates, but because of its local abundance, "the rowhouse is Baltimore's special insignia," writes Natalie Shivers in her 1981 history, "Those Old Placid Rows: The Aesthetic and Development of the Baltimore Rowhouse." And in this city and its outskirts, in Formstone rows and county town homes, from one end-of-the-row to the other, people struggle daily with the challenge of living cheek by jowl.

Built as a unit, rowhouses are hard to separate one from the other. That's a plus in winter, when each abode helps keep its neighbor warm. But where does one rowhouse roof end and the other begin? Should you ask permission before building a fence? What if your walnut tree is dropping nuts all over the neighbor's deck? If you mow your lawn, but the neighbor doesn't, what's the point? How long does one tolerate living between two people who watch their televisions at top volume?

In the process of wrestling with these dilemmas, rowhouse society has engendered its own, ever-evolving etiquette. "If you want to live in a rowhouse, you have to act like a rowhouse person, not like someone who lives in the middle of the forest," as one rowhouse veteran puts it.

Old-fashioned courtesies, such as leaving couples alone to court on front porches, have gone the way of trolleys, but good neighbors still water one another's gardens, guard against mischief, take turns watching neighborhood broods.

"We all try to live by the Golden Rule. I think that's the secret," says Helen Warehime of Highlandtown, who breaks into a crinkly smile and offers a slice of coffeecake when a visitor arrives at her doorstep.

Eagerly, she talks about the web of friendship and concern that enfolds the 600 block of S. Streeper Street. Just the other day, when she was short four potatoes, she simply hollered three backyards over to Shirley Janiak, who was hanging the wash. Later, Mrs. Warehime, 73, delivered homemade chicken and dumplings (with potatoes, of course) to elderly neighbors on her block.

A widow, Mrs. Warehime raised four children on Streeper Street and has lived there almost all her life. Thirteen houses on the 40-home block have passed from at least one generation to another, she says. "That's what's keeping the neighborhood up. It's not strangers, it's people who had roots here all their lives."

Streeper Street residents are vigilant. "If a stranger is hanging around, neighbors call each other and tell everyone to be on the lookout," Mrs. Warehime says. "If my lights are on later than usual, I will get a phone call to see if I'm OK."

In summer, the neighbors grill hot dogs and hamburgers or get up a crab feast while the kids play dodge ball in the street. When there is a death on the block, "We send flowers with a neighbor ribbon," Mrs. Warehime says. It's a tradition she inherited from previous residents some 30 years ago.

Though new, a suburban rowhouse development can cultivate its own neighborhood traditions. Vivian Worthington lives in such a community in Perry Hall. She has a photograph snapped during a blizzard last winter. In it, "Everybody is shoveling as a group . . . others would cart the snow to the other side of the street. It just was wonderful. I just love living here," Mrs. Worthington says.

In good weather, Mrs. Worthington and her neighbors spontaneously gather at their mailboxes on Friday evenings for happy hour while the children frolic nearby. "We all have such a connection. We're all first-time homeowners, we're all on our first marriage," Mrs. Worthington says. "We're all experiencing life's difficulties and decisions at the same time."

As generations of sprouting families have done before them, Mrs. Worthington and her neighbors will probably leave their starter homes eventually -- with reluctance. "None of us wants to move, and if we do move, we want to take us all with us," she says.

A united rowhouse block can also be a fortress against urban decay. By coalescing into an extended family, the residents of Tina Brown's block in the city community of Upton have resisted the surrounding drug scourge.

"Everyone tries to keep the block clean," Ms. Brown says. "And believe it or not, everyone comes home and has their own parking space in front of the house. I find that so amazing."

When Ms. Brown leaves for work, her neighbor watches as she gets into the car. And when there's a fight on the block, "the whole neighborhood comes out," she says.

It's not perfect. The playground across the street, for example, has been wrested from the little children by a gang of older, tougher kids. Ms. Brown and her neighbors are campaigning to shut it down. And one block up, the drug trade flourishes.

"I feel we can actually go places," says Ms. Brown, recently tapped to head her neighborhood association, "as long as we can keep drugs out of the block and off the corner."

Close quarters

Of course, the power of proximity works both ways: One neighbor's privacy fence can be another's Great Wall. Chartreuse trim can throw an entire row into chaos. A kid cannonballing into an above-ground pool can mean a chlorine bath for you. Even that sweet lady who makes sure you're tucked into your home at night can readily metamorphose into a ruthless snoop.

And a warning to the disaffected: When a Baltimore rowhouse owner built a cinder-block wall on his front porch to avoid seeing his neighbor, the city made him tear it down.

The law also intervened between neighbors in Tuscany-Canterbury, an upscale Baltimore community of Tudor-style rowhouses.

Here, Linda and Bill Eberhart first applied for a zoning variance in 1988 to build a 20-by-26-foot deck behind their Tuscany Road rowhouse. Outraged by the proposed dimensions, the Eberharts' next-door neighbor, Lewis Kann, enlisted his law partner to fight the deck.

"It's an invasion of privacy to have people standing there looking at me in my breakfast room while I'm eating or working," Mr. Kann says.

Equally determined, the Eberharts retained well-known attorney M. Albert Figinski to represent them. The deck remained partially built during a series of reversals by the city's housing and zoning agencies and the courts.

Last month, for the second time, the dispute was argued before the Court of Special Appeals. On May 20, the state's second highest court upheld the Eberharts' variance. Mr. Kann is considering whether to take the case to the Court of Appeals.

If Mrs. Eberhart had known what grief the deck would cause, she wouldn't have bothered. "It's just been a nightmare," the Baltimore City elementary school teacher says.

But after a certain point, it was too late to retreat. Defending the deck became a matter of principle for her husband, Mrs. Eberhart says with weary resignation.

With or without decks, rowhouse dwellers must create their own illusion of privacy. Discreetly, they file the flushing toilets, noisy disagreements and sexual antics next door in the "out of sight, out of mind" basket and pray their neighbors do the same.

Privacy matters

Even illusory privacy is hard to come by on Small Court, a cozy rowhouse cul de sac in Catonsville filled nightly with socializing families and an inordinate number of newborns (considering the general lack of seclusion.)

Residents "have a very watchful eye . . . even too much so, if you know what I mean," says Jeff Natterman. "When we first moved in and were scraping the master bedroom. I looked out the window and a bunch of neighbors were looking in the window, staring. It was our first taste of [realizing] everyone knows what everyone else is doing."

Mr. Natterman, 39, was also informed that while he was in the bathroom, passers-by could "see my shadow in the Venetian blinds. There's no secrets. I have to very creatively not cast a shadow in the wrong direction."

And not long ago, the Nattermans' daughter, Elizabeth, fell out of bed with a crash. The next day, their neighbors asked if she was OK. The Nattermans, heavy sleepers, had not heard a thing.

After almost buying a detached home recently, the Nattermans reconsidered. "It's so vibrant here," Mr. Natterman says.

Whether they want to or not, rowhouse residents must learn the art of negotiating with neighbors.

The rowhouse lifestyle takes "tolerance and patience," says Dale E. Livingston, a community activist in Knettishall, east of Towson. "You also learn you have to communicate with people. When you live in a single family home, you don't have to communicate with anybody."

When their immediate neighbor wanted to build a patio across both back yards, the Livingstons were at first not keen on the idea. Then, "We started talking to him, and decided that it would look nice to have a common patio," Mrs. Livingston says.

Now, the neighbor is moving. "But who cares? It will work out, I'm sure," she says.

Neighborly disputes

Mr. Natterman has also been forced to hone his neighbor negotiation skills. Every year, he is assaulted by the bracing fragrance of mothballs, crushed and spread by his neighbor to discourage squirrels. Last year, he built a picket fence to keep his toddler from wandering into the mothball yard and asked his neighbor, to no avail, to remove them.

This year, when Mr. Natterman came home to find the mothballs had reappeared and his pregnant wife in tears, he marched next door and told his neighbor to remove them, pronto. "I don't want to be an enemy, I want to be a neighbor," Mr. Natterman recalls saying.

This time, the neighbor removed the mothballs.

Others who live in rowhouses may find they cannot control their environment, perhaps the lifestyle's greatest flaw. Once immaculate, Helen Gold's Brooklyn rowhouse block is now crumbling and trash-strewn.

"I'm livid, oh I tell you . . . I have a neighbor two doors away, she's just as disgusted as I am. I just think we overstayed. If I could just pick this house up and put it in an another area I would be tickled pink," she says.

Mrs. Gold lives across from her childhood home. She returned from Glen Burnie in 1970 to tend to her ill father. "I was so desperate to be near him. I'm not sorry I did that," she says.

Now, Mrs. Gold is in a fix. "My house is paid for. I'm 50 years old, and I don't want to go into another mortgage," she says. "This place is probably going to wind up killing me."

But over on a narrow, sloping street in Upper Fells Point, a joyous rowhouse odyssey is just beginning for Alyssa Merkel, 23.

Last year, against her mother's wishes, Ms. Merkel bought a house that needed a lot of work. At first, she remembers thinking: "What have I done? Was my mother right? I don't know anyone in the city. What if something happens to me?"

Her fear swiftly evaporated as Ms. Merkel came to know the neighbors two doors down, a retired city policeman and his wife. They took Ms. Merkel under their wing, inviting her over for Saturday breakfast and stuffed cabbage feasts. At night, they sit on their neighboring stoops and listening to the Orioles game on the radio.

"I couldn't be happier," says Ms. Merkel, who grew up in Bowie. "I still think my mother isn't happy with the fact that her baby moved to the city by herself, but I think she feels better knowing there are people there looking out for me."