The open-air food market is a disappearing institution, largely displaced by the antiseptic supermarket. The Haymarket of Boston is a tenacious if precarious twentieth-century survival, but one which happily could hardly be more full of life and spirit than on Fridays and Saturdays, when the individually-owned pushcarts of the produce vendors join the meat men, who operate all week from adjacent store fronts and cellars. In one form or another, this market in the heart of town has been open for some 300 years, and its sights and sounds, its aroma and flavor, combine to produce a total experience for everybody there.The sights and sounds of Haymarket have been captured live by Wendy Snyder, a teacher of photography. She has spent many hours with its people, recording her impressions on film and tape. The result, "Haymarket, " alternates some 60 candid photographs of the district and its citizens with the candid vernacular of their talk--on themselves, the market, the customers, their families and friends, the past, their hopes...on everything from the price of tomatoes to the meaning of life.Most of the market men are the sons of emigrants from Italy, Sicily, Greece, Ireland, and other European countries. These, and Jews and Negroes, work side by side at their stalls, openly and good-naturedly denigrating each other's ethnic backgrounds. They differ in other ways: Some bring their sons into the business while others use their market profits to put their sons through college; some have other jobs during the week while others bet at the race track or follow the stock market. But all the market men are united by a common tradition and lifestyle that are vividly expressed in their portraits and in their words.