Dentists are doing it. So are psychiatrists, drifters, government employes, journalists and teachers. Buried in little literary nooks all over Washington, these people are trying to write books and work at the same time.

The result of their labors may not always be the Great American Novel, but it's ouevre.

Is it possible to pull off? "Writing's the greatest thing to do," says local writer Barbara Esstman, but "there's a lot of giving up things . . . The hardest thing is to keep one foot in the real world, and write."

Although William Faulkner wrote his early poetry while a postmaster at the University of Mississippi and Nathanael West suffered jobs as a hotel manager and magazine editor, the great work came later, uninterrupted by the constraints of 9-to-5. As a young Herman Melville complained to his sister in 1820, "No man can be a poet and a book keeper at the same time."

Allan Lefcowitz, founder of the Writer's Center in Bethesda, sees a groundswell of hopeful scribes based in Washington. "There are so many writers who are working full-time, with letters out to publishers," he says, "it would be difficult for me to single out any as being special."

Of the 2,500 "supporting members" of the center, Lefcowitz estimates 40 percent are "working on novels," in various stages, at varying levels of employment. About 300 people are in government, "working in everything from agriculture to the State Department." Many are full-time teachers and the remainder work in professions "pretty much spanning what's happening in the Washington area."

The writers defy more generalization than that. Especially if you consider ones like Rod Willoughby, 32, a postman who wrote a novel called The Oldest Feud, a children's book about the eternal conflict between dog and mailman; or former District police chief Jerry Wilson, 57, who took after-dinner walks in the early 1970s to dictate chapters of his book into his tape recorder. He would have the notes transcribed and edit them on Saturdays, for a collection of observations called Police Report.

One thing most of these writers have in common is the uncomfortable knowledge that writing full-time is essentially for the rich or thoroughly published. "Even if you are writing the great American novel," says local literary agent Audrey Wolf, "you'd better do it in your spare time. Because even if you have dreams of glory and huge advances, there's a big slip between cup and lip."

For moonlight scribes, the main question is "How?" With all the constraints on their time and pockets, they must willingly suffer one or more of the inevitable variables: poverty (if they quit working or switch to parttime), self-doubt, fatigue and loss of social life. And forget the oil change on the family car.

In theory, early mornings, nights and weekends are creative prime time. But those hours have to contend with other extracurricular interruptions -- nighttime sleep and marriage come to mind. Unless they can quit work and write a novel on no income, writers have little choice but to cut back on other activities. "The problem is," says Washington novelist, playwright and writing teacher Patricia Griffiths, "when do you live? You have to live to have something to write about."

"It usually doesn't work," author/lecturer/critic Doris Grumbach says of would-be authors juggling job and novel. She advises them to work for a while and save some money, then "hole up in a cheap place; or -- if they are qualified -- apply to work at a writer's workshop where they can teach a course and write the rest of the time . . .

"A novel is a long-term, concentrated piece of work that absorbs your whole being, your whole soul. Your job is usually a public thing, and that seems to use up the writer's total energies."

Even if a writer manages to complete a novel while finessing the Day-to-Day, questions remain as to the quality of the finished product. "Preconditions to writing often determine how good or bad the product is," says Washington-based James Grady, 36, who wrote Six Days of the Condor.

"I suppose anything's possible," says Richard Bausch, 40, a writing professor at George Mason University. "I kind of doubt it, though. It's like saying, 'Be a concert pianist while working at a gas station.' "

"I wrote the first novel [while] working full-time," says Ted Mooney, 34, raised in Washington and now living in New York. He completed Easy Travel to Other Planets over 3 1/2 years, while editing full-time for Art in America magazine. The book sold more than 100,000 copies.

Mooney wrote in the mornings, from 4:30 to 8:30. "There's something quite lovely about it," he says of twilight writing -- before the onslaught of rush hour when "nothing else has happened in the day." And, he says, "you get acclimatized" to the time schedule.

A veteran of the double life, Alan Bisbort, 32, manages two jobs that have him working six days a week. He shelves books at the Library of Congress and works at a bookstore. The product of his labors, he says, is 2 1/2 unpublished novels.

"I get up at 5 a.m. and write until 8:30. Then I catch my bus to work; I dress at the bus stop. It's sort of like being an athlete," says Bisbort, who gets home after work at 9 and is in bed by 10.

Barbara Esstman, 38, writes short stories when she is not taking graduate courses at George Mason, teaching at the same university part-time, and shepherding her children to ballet and soccer practice. She gets in six hours of writing "in a good week," she says.

"I think what I do mainly is budget time like crazy. I try to clear everything else out of the way and work double-time when there are other things going on. But this Tuesday was blown out of the water. I had 55 10-page papers to grade." When she has time to herself, "I'm a recluse. I'm antisocial."

Mary Lide, in her late forties, who recently completed a trilogy of historical novels, spent nine months employed at the International Monetary Fund while working on the second book. She clocked in some 30 hours' writing a week, through weekends, and on weekdays from 4 to 8 a.m., or from 8 p.m. "until I felt I had to go to sleep, I guess . . ."

But, she says, "it was very, very exhausting. . . I don't think I've ever worked so hard since I took my college finals."

Writers soon discover the ramifications of cutting back on their personal lives. Although Mooney socialized on weekends, friends found it hard to appreciate his early-morning schedule during the week: "They'd be insulted if I refused to attend a party that began at 9."

Bisbort says he has had to alter his "deepest and darkest inclinations, which are to stay out drinking at night." Says Lide, who eventually quit the IMF job to write full-time, "You give up, essentially, a social life, and you have to have very understanding family and friends." Like many other full-time writers, she remembers the days of work and writing with a certain bemused horror.

Richard Bausch managed to produce a first novel while "teaching seven courses at three different schools." He wrote from midnight to 4 a.m. and took catnaps in the afternoon after classes. However, he points out, he doesn't need much sleep anyway and "my first novel is not a great novel."

Patricia Griffith tried writing short stories and working in public relations in New York, but found it "pretty tough . . . I worked till my husband had a regular check, stopped and started to write full time, taking up parttime work here and there." She now teaches fiction at the Writer's Center and edits part-time.

Writing and working together "can be done," she says, citing Joseph Heller (who wrote Catch-22 while working as an advertising copywriter at McCall's magazine). "But most novelists I know are writing full-time, or writing and teaching."

Which brings up a significant question for writers who must find employment: Can they insulate their writing acumen by working at something completely different, or should they attempt to do something supposedly complementary to their craft, such as teaching?

Doris Grumbach prefers lecturing and criticism to teaching for her pickup work. "It isn't only outside jobs" that interfere with writing, she says, "it's other people's work."

Teaching has a dual capacity, says Jim Grady: "On the one hand you're invigorated and, on the other, you're polluted." Grady tried inspecting fire hydrants for a municipal water department in Montana while he wrote. "I wanted a job that would pay me enough to live on and not use up my mind." He lasted five weeks, because "whatever energy I was saving from not dealing with the written word, I was using up in frustration by not being able to use my talents and skills."

While writers wring their hands yearning for free time and mythical advances from publishers, neither is what it's cracked up to be. If a first-time writer gets an advance of $5,000, he or she has all but struck oil, says Jim Grady. And free time without discipline is not free time, says former journalist Dan Rapaport, 52, who now heads Farragut Publishing here. Rapaport says he got more written when he was working than when he took time off from his former job to write. "When you have all day long," he says, "you tend to get soft. You don't feel pushed."

In addition, he argues, if a writer writes before work, the ensuing fatigue can be overcome by the momentum of the working day. "If you do get sleepy, you're doing it on company time."

Assuming writers have found a relatively compatible job, there is still the battle against attrition. How to keep going? When fatigue sets in, ambition wavers and any problems writing the novel are magnified.

"You have doubts every so often," says Ted Mooney, who says a confidence in his material helped him through the difficult times. "You know that sometime in those years of effort you're going to hit a rough patch and you just go through it. You get stuck on a character, a bit of action. You might not be sure you'll pull off a given scene. I was absolutely determined to do that book. I liked the first 50 pages of the novel enough so that I didn't want to let them go, under any circumstances."

However, Mooney -- well into a second novel -- works part-time and now writes from 8 a.m. till noon.

"The only way I can think of it is 'Nose to the grindstone,' " says Bisbort, who plans to complete his novel by spring. "Do it every day whether you're sick or well . . . I don't ever question myself.

"I've been rejected [by publishers] too many times. It's a perverse streak that says that if this many people don't like what I'm doing, I must be doing something right. Rejection and being anonymous and still carrying on with what you want to do just makes you stronger."

While the constraints and sacrifices may be formidable, the opportunity to write something that one hopes is significant is worth it, say many writers. Not to mention the murky possibility the book will be published. "Writing is a real act of faith," says Grady, "that somehow you're going to overcome all these odds and someone will read you."

Lefcowitz sees potential for a fiction-writing industry here. With "a critical mass" of Washington writers, writing everything from gothic romance to "growing-up novels," the ranks, he feels, may attract publishing houses to set up shop in the District. "Who's doing it? Everybody," he declares. "Where are they? They are everywhere. And that is literally true."