A man named Ryan answered my "room-wanted" ad in the newspaper and said he and his girlfriend had a house to share in A.U. Park.

"We're very quiet," he said, "and the house has three bedrooms and a fireplace. There's a sauna in the basement and the rule is the first one to get home in the evening turns on the sauna."

Sounded too good to be true.

"I'm away a lot on business," he added. "Would you mind being alone with Jennifer? She's a graduate student in art at A.U. and conducts modeling classes in her studio on the second floor. But that's only on Thursday afternoons."

"No problem," I said.

Then came the kicker.

"Occasionally," he said, "she likes to walk around the house in the nude. Would that make you uncomfortable?"

No matter how attractive a shared living situation sounds, there's usually a catch somewhere.

I learned all this after spending five intense weeks searching for a house to rent with a small group. I was "riffed" by my landlady who, after our lease expired, decided she wanted to get back in her house. The news hit me like a death sentence. Next to losing a job or terminating a romance, there is nothing quite so disruptive as being forced to find another place to call home.

In my case the experience was doubly painful. As a single who likes to live with other singles and can't afford to live alone, I had an ideal situation: clean, spacious townhouse (with fireplace, of course), a congenial housemate and a quiet neighborhood in an attractive area of the city. My standards were high.

I put the ad in the paper confidently, but abandoned the idea after a week in which Ryan was my only heterosexual response.

Then I began poring over the "to-share" classifieds like a law graduate studying for the bar exam. I lost touch with other sections of the paper. Somebody told me that the baseball strike had ended.

In the highly condensed literary form of the classified ad some of the abbreviations are real beauts:

GLOVER PARK -- Prof. professional? M/F to shr. spac. 3 br. hse. with same. $275 plus 1/3.

BETH/CH CH -- $225. Walk NIH funny name for a dog w/w, CAC, Lg. Bk. yd., W/D, FP, no smoke A fireplace without smoke? Oh, non-smoker. I smoke cigars, but after she meets me, maybe Beth Ch Ch won't mind.

What these ads don't mention is sexual -- as opposed to gender -- preference, but the subject invariably comes up. It's part of the ritual of meeting a prospective housemate and usually follows the tour of the house.

Relations among members of a coed house are by and large platonic. Daily contact with the opposite sex tends not to promote sexual relations but to evoke the fraternal-protective instinct. Happy or not, you are brothers and sisters. And relations stop accordingly at the bedroom door.

Speaking of bedrooms, hundreds out there are way overpriced and not fit to sleep in. Basement bedrooms -- or the Black Holes of Calcutta -- go for $350 and up.

I was impressed by Judy's Georgetown townhouse until she showed me The Room: a large walk-in closet with barely enough space for a double bed and waste basket. Judy was more attractive than the room and we are now seeing each other socially.

Answering other ads, I found similarly not a room but friends: Lucia, who plays tennis; Sharon, who loves foreign films; and Mitch, a third-year law student.

While living habits and compatibility are important, the decision whether to move into a house or not ultimately boils down to a gut feeling: Do I really want to live with these people?

Rick and Bob, two young lawyers, live in a nicely-furnished, conveniently-situated house. But they couldn't seem to agree on one basic point.

"How do you feel about overnight guests?" asked Bob. "Rick's girl is here at least three nights a week and I usually stay over at my girl's house."

The phone rang and Bob went to answer it.

"He doesn't care for my girl," said Rick. "That's why he's making such an issue of this."

Bob likes everything cool. "We like to keep the house at 60 degrees in the winter," he said. "That's why we advertised for a conservation-minded housemate."

Samantha, a divorced businesswoman who owns a $250,000 white brick, cedar shake house in Potomac, had a string of live-in boyfriends, the last of whom she bailed out of bankruptcy.

"Then he left me, and I haven't gotten a single penny from him.

"I'm trapped. I can't sell this house, not at these interest rates, and if I move out and try to rent it, I would lose even more money. That's why I need a housemate."

It ain't me, Babe.

Then I responded to an ad that sounded promising. "Hello," I said to the elderly man on the other end of the line, "is the room still vacant?"

"Yeahzz," he slurred. "Excuuse me, I muz call the . . . " He hung up. When I called several days later, the man's nephew told me his uncle had had a stroke and was in the hospital.

Finally, after weeks of investing literally 4-5 hours a day on the project I had a stroke of luck: Roommates Preferred, one of several housemate-matching services in town, referred me to an economist named Karl and a Capitol Hill staffer named Harry.

I felt comfortable around them both and I liked their townhouse in Georgetown.

"We'd like you to move in with us," said Harry two days after our meeting. "Will Saturday be okay?"

"Yes, indeed, Harry."