IF WASHINGTON has not been known as the publishing capital of the Western world, it may have been for want of a quiet place where inkminded people could sit down and talk to each other.

The lack was remedied with daring directness about 18 months ago when William Begell, president of Hemisphere Publishing Corporation, invited three publishing friends to invite some of their publishing friends - chain-letter fashion - to meet at his Connecticut Avenue apartment. By the time the group had polished off Mrs. Begell's Chinese chicken with plum sauce, Chinese celery salad, quiche and warm with almonds and grapes, they decided they'd better meet again. As the word spread and they outgrew the Begell kitchen, they decided to organize. Now, as The Washington Book Publishers, with 133 members from 74 publishing organizations, the group convenes about six times a year in a conference room of the Carnegie Endowment for International Peace - over cheese and crackers and beer.

By the time you add up the list - from the one-person operations to the university presses, learned societies, trade associations, foundations, magazine book divisions, specialized technical publishers, and the many-splendored outpourings of the U.S. Government - you can see that printing is one of the major industries and largest employers in the city.

"There's a lot of publishing going on in Washington that people didn't know about," says Mark Carroll, secretary of the new group and chief of professional publications for the National Park Service, where they turn out some ten handsome volumes a year on history, archaelogy and architecture. "Some publishers didn't even realize they were publishers. One purpose of our meetings was to raise the consciousness level of people in publishing," he explains.

With the vigorous expansion of recent years, the city is turning into "a distinct, measurable publishing center," Carroll thinks. Time-Life Books added 375 people and 35 books a year to the picture when it moved to Alexandria last year. The National Geographic, The New Republic, U.S. News & World Report and The Washingtonian all have book divisions.Some of the newsletter publishers are mini-conglomerates. Capitol Publication, Inc., a medium-sized outfit, puts out 19 newsletters, distributes other publishers' books by direct mail and publishes a growing list of books of its own. (In fact, newsletter publishers may be the town's biggest employers of journalists and have lately established a Newsletter Association - but we'll get to that later.)

McGraw Hill, Doubleday, Harcourt Brace Jovanovich, Prentice-Hall and Houghton Mifflin now have permanent representatives here instead of sending periodic scouting parties to case the terrain. International Creative Management, the huge New York talent agency, has hired Esther Newburg to specialize in Washington man - Townsend Hoopes, author of The Devil and John Foster Dulles: The Diplomacy of the Eisenhower Era and The Limits of Intervention (1969), a critical look at President Johnson's Vietnam policy. The American Institute of Graphic Arts has a 100-member Washington chapter, headed by Howard Paine, art director of the National Geographic. There is a Washington Booksellers Association, headed by William Farnam of the Smithsonian bookstore, and a growing underground of one person or specialized publishing operations is tucked away in odd corners all over town.