The early days of Dublin's famed Abbey Theatre live again each day at Lamont when the tall, distinguished-looking professor with the shock of gray hair, the shaggy eyebrows, the searching blue eyes and the soft accent begins to lecture. Denis Johnston, visiting professor of Modern Irish Literature, wrote plays for the Abbey during the exciting years when its opening nights made news around the world.

It was W. B. Yeats who encouraged Johnston on the playwright's path. The Professor has carefully preserved the manuscript of his first Abbey play complete with Yeats' carefully written comments and corrections. Seven plays followed the first Johnston drama, "The Old Lady Says No," but the writer likes best his second play, "The Moon in Yellow River." This summer he hopes to complete another drama with a background of the Irish Revolution. Like many Irish playwrights, Johnston has a superstition which prevents talk about a play not yet published. "Irishmen feel if you talk too much about a play, there's a fair chance it will never see print," he explains.

Last winter, on leave from Mount Holyoke College where he is professor of English, Johnston returned to Dublin to collect data for a biography of Dean Swift which he is completing under a Guggenheim Fellowship. Three years ago he published the autobiographical "Nine Rivers from Jordan," which dealt with his experiences as a war correspondent in the Middle East, Germany, France and Italy.

Johnston was a graduate law student at Harvard thirty years ago, at the same time Adlai Stevenson was here. Most of his formal schooling was earlier completed in England, however, largely at Christ's College, Cambridge.

The Dublin-born writer says that despite interval careers as teacher, war correspondent and B.B.C. program director, his first love is the theater. He has not only written plays but acted in them and directed them, notably at the Gate Theatre in Dublin and on this side of the ocean at the Province-town Playhouse and the Amherst Theatre Festival. He has high praise for the Poets' Workshop Theatre here, and is very much in favor of repertoire theater, since it gives the playwright a chance to see his work enacted and to revise it.

The current widespread interest in Irish literature and the popularity of his Summer School course on the subject are no surprise to Johnston. The Professor singles out James Joyce as the greatest prose writer of the twentieth century. He feels that the literary scene in Ireland today lacks an authoritative spokesman because the new Republic hasn't yet made up its mind what it is going to be. This situation is good, Johnston feels, because it indicates that the fulfillment of his country still lies in the future.