Potent Greek drama at a dizzying pace -- in Williamstown, Mass.

The Williamstown Theater Festival has turned itself into one of the Northeast's premier summer theaters. As the years tick by -- and this is the 27th season for the festival -- the list of actors willing to devote a summer or part of it on director Nikos Psacharopoulos's summer group gets stronger and stronger. This year marks something of a pinnacle in terms of the names involved: among them Edward Herrmann, Richard Chamberlain, Richard Dreyfuss, Christopher Reeves, Roberta Maxwell, Blythe Danner, Celeste Holm, and Pamela Payton-Wright.

This season has opened with an ambitious risk -- a two-part distillation of the 10 plays that make up the story of the fall of the House of Atreus. The story is given in two evenings of drama -- "The Blessed" and "The Cursed" (collectively titled "The Greeks"). Under the most generous circumstances, this is a risky undertaking. Under summer festival conditions, it would appear nigh impossible, better suited for Stratford, Ontario.

Mr. Psacharopoulos's direction here has to be among his finest efforts ever. Experiencing this huge two-part saga (reduced from the three evenings it took in London) is something like studying topography from a low-flying plane: Events and confrontations whiz by with dizzying rapidity and a certain lack of depth. Yet the cycle is compelling and the stories, told in an uninterrupted line, have a visceral impact and uncommon continuity.

In such a case it seems useless to question why there is not forum in the United States -- particularly in New york -- for clasical theater. One can sense that the fine actors seen in this play have a good grasp of the roles, though not as finely tuned, in several cases, as one might wish to have.

Naturally when such a generalization is made, there are performances that contradict it -- Miss Maxwell's stunning Electra, Maria Tucci's haunting Andromache, George Morforgen in his various roles, and Miss Payton-Wright as Cassandra. Others were at odds with their parts, still others made their assets count when needed -- Jane White's spectacularly resonant voice made for a rare Clytemnestra; Josef Sommer's strength and world-weary daze proved ideal for Menelaus; Donald Moffat's curiously ambivalent presence underscored Agamemnon's weakness at so many key points.

One could also cite moments supplied by Frank Maraden as Talthybius, the welcome moments of high humor from Carrie Nye as a magnificent and funny Helen, the bitter hardened side of Roxanne Hart's Iphegenia in Taurus.

Overall it is the spirit and vitality of Greek tragedy that is celebrated here. The John Barton-Kenneth Cavander adaptation tries to bring it in line with today's conventions without betraying the essence of Greek tragedy. There is an irony, a contemporary vigor to the meter of the language, and an attempt to make the emotions as elemental as possible.

What is lost in the formalized grace and the remarkable mechanics of the 10 original plays is replaced with something altogether engrossing -- the problems humans endure in every age.

This version also makes us aware of how vital voice is the women's chorus --handled with particular deftness by Mr. Psacharopoulos. This voice rejoices in the uplifting moments, suffers with the sufferers, and generally expresses the collective cares and woes of mankind as affected by the actions of the principals in this great epic drama.

One could have done without the "Zorba the Greek" gestures and dances, and particularly without the original music, which was mostly intrusive, rarely to the point. John Conklin's set is a thrilling unit -- all grays, with a Stonehenge-like structure stage left, and a small alter stage right. Above the players floats the gigantic mask of Zeus and (one assumes) Hera, expressionless, stony, silent.

"The Greeks" runs through July 18, followed by Shaw's "Arms and the Man" July 24-Aug. 1 and Gorky's "summerfolk" Aug. 4- 8. There will be two more productions, as yet unannounced.