I want to be alone. -Greta Garbo

And the Lord God said, It is not good that the man should be alone. -Old Testament: Genesis, 550 B.C.

I am never less alone than when alone. -Scipio Africanus, 200 B.C.

Better be alone than in ill company. -John Ray, Scottish Prverbs.

We walk alone in the world. Friends, such as we desire, are dreams and fables. -R.W. Emerson, 1841

There is no man alone, because every man is a Microcosm, anb carries the whole world about him. -Sir Thomas Browne, 1643

YOU MAY, upon waking Christmas morning, peer out your window to find a world that looks like a post atomic-bomb scene from the movie "On the Beach." It is not your imagination. No one is out there.

Tomorrow is one of the few days in the year when nearly everyone says "Enough!" and stays home. Streets are empty. Museums are closed. The monuments are shut down. Even the YMCA, immortalized in a recent hit record as the place you can go when down and out, is off for the day.

If you are planning to spend Christmas day alone, you can count on no one bothering you. If you don't particularly care for the idea, you have a problem. Some ideas for beating the Christmas blues:

Stand on the roof of your building flapping your arms. Sooner or later you are bound to attract the attention of someone in authority who will have you placed somewhere where you will not be alone.

Take position on a street corner without a wrap. After a few hours in the elements you will begin thinking how much better off you you are than people who suffer wars, typhoons and earthquakes. You also will be so cold you will forget about being lonely.

Open your window, stick your head out and scream, "I won't take it any more." The primal scream is said to be therapeutic.

Go back to bed. Pull the covers over your head. Cry until New Year's.

So much for home cures.

"Most people don't chose to be alone," says William Sneck, S.J., a clinical psychologist at Georgetown University. "The remedy is just old-fashioned getting busy.

Of course, anyone who's ever spent a Christmas on his lonesome knows getting busy takes guts. Some authorities in the mental health business suggest helping someone else as most satisfactory.

For instance, organizations such as the Salvation Army, Catholic Charities and the District's emergency shelters gladly accept used clothing, canned goods, toys and furniture. Tomorrow might be the time to clean up around the house, in the attic and in the celler, collecting all the unwantables and dropping them off for the needy. You can also leave fresh produce. And if you feel especially sympathetic and energetic, you might bake pies, cakes, cookies and anything else for the hungry.

"We accept anything," said Ira Williams at SOME (So Others Might Eat). Guy Jones, the executive director of Northwest Settlement House, is opening the Settlement House doors tomorrow at 10:30 until 12:30 for donations of food (including fresh vegetables, salt, margarine and meats). Christ House, in Alexandria, the Salvation Army and the National Shrine are among the places where volunteers may also give by helping serve a meal.

At the **district's family shelters, "There were several families who didn't have anything last year," said Sarah Williams at the shelter in Southeast Washington. Children there can use toys and clothing.

Here's a list of charities open tomorrow, and their phone numbers:

Christ House-131 S. West St., Alexanderia; 548-4227.

SOME-71 O St. NW, Washington; 332-2220.

Northwest Settlement House-448 Ridge St. NW (near the intersection of M and N and 4th and 5th), Washington; 638-4736.

Salvation Army-(headquarters) 909 I St. NW, Washington (they served about 300 meals last Christmas); 783-4050. A center for about 80 men is at 526 1st St. NW. and a shelter for women and children is located at 504 5th St. NW.

D.C. Mergency Family Shelters-1531 P St. NW; 673-7694. And 2850 Hartford St. SE; 767-7890 (around 30 children are housed here).

Or you can visit the local hospital where other lonely people might enjoy chatting. People who have done this say they were completely uplifted by the experience.

The church is another place people congregate. And no one need mind coming alone. Although most churches celebrate on Christmas Eve, a few have services tomorrow. Those at the National Cathedral (near the intersection of Massachusetts and Wisconsin Avenues NW) begin at 10 a.m. and will be televised. Others are at Old St. Mary's Church at 5th and G Streets NW (10, 11:30 and 1); The Franciscan Monastery at 14th and Quincy NE (masses hourly from 6 a.m. to 12:15); The National Shrine at 4th and Michigan Ave. NE (Cardinal William Baum celebrates the noon liturgy).

If, after altruistic endeavors, you are still left with spare time, you can take the car up to the Jewish Community Center (6125 Montrose Rd., Rockville, 881-0100) for the Hanukkah celebration from 1 p.m. till 5. Besides dancing and singing and dradle making, participants will watch a torchlighting ceremony and fire writing (traditional Jewish events) at dusk. Volunteers begin a marathon swim and jog attempting to accumulate the total mileage to Israel. (Kibbutznik counterparts in Israel are doing the same simultaneously.) Admission is free.

Then there are television and radio, which mostly have forgotten about the lonely people out there who would prefer hearing people talk and say funny things. Most television and radio talk shows unfortunately are replaced by holiday music tomorrow.

Father Sneck, for one, thinks that's a shame because, "Talk shows are probably the least energy-demanding way of getting involved with other people. People alone in apartments relate to the announcers and to the others who call in."

"Most people are involved with what they're doing-opening packages and being with other people," said one programmer at WJLA's "AM Washington-normally a talk show.

You might tune in Sherry Berger's WPGC radio show this morning, from 9 o'clock till 10, when she plans to talk with psychologists and social workers about what people can do to escape loneliness on Christmas day. WPGC is at 95.5 FM and 15.8 AM.

WRC News Radio, 98.0 on the dial, brings a day of live Christmas broadcasts and call-in shows tomorrow.

Or you can share the holiday with family and friends in faraway places by taking advantage of the phone company's holiday rates. A call to Seattle is 35 cents for the first minute, 25 cents for each minute after that. Chepest rates, however, are after 11 p.m.

The national monuments are closed tomorrow. But they will be lit as usual for strolling on the Mall and along the Tidal Basin. Sunset is 4:51. You can walk to the Ellipse and watch the lighting of the Christmas trees, or try figure-eights on the ice rink near the National Gallery (open all day till 11 p.m.). And if you have adventure in your heart, you can cruise the city in search of the light fantastic and apartment buildings in the act of celebrating.

If you are the type who can spend a meal alone without feeling the walls closing in on you, some restaurants will be open. Check the hotels. Many Chinese places will be serving, as will popular spots such as the America Cafe in Georgetown.

You can partake of a Christmas meal at the First Congregational Church (10th and G Streets NW), the National Shrine cafeteria or at St. Alban's Church (Massachusetts and Wisconsin Avenues NW).

For your amusement, Eugene O'Neill's comedy "Ah, Wilderness!" is playing at Arena Stage. New Playwrights' Theatre shows "A Christmas Carol." Check "Showtimes" for a complete listing of theater and movie offerings.

But if you just want to talk to someone who'll listen to your Christmas woes, you need go no farther than the phone. To find someone who'll wish you a Merry Christmas, choose from one of the several area hotlines:

Northern Virginia-527-4077.

Alexandria-548-3810.

District of Columbia-462-6690.

Montgomery County-949-6603.

Prince George's County-864-7271.

Merry Christmas.