A tale of irony and pessimism set in the land of promise; The Ballad of Typhoid Mary, by J.F. Federspiel. New York: E.P. Dutton. 169 pp. $ 12.95.

An unusual book has just appeared on the American literary scene, raising eyebrows and winning enthusiastic reviews: ''The Ballad of Typhoid Mary,'' by J.F. Federspiel.

So enthusiastic were the reviews, in fact, that even before its Jan. 31 publication date its American publisher, E.P. Dutton, had already ''gone back to press'' to order additional copies.

Why the enthusiasm?

J.F. Federspiel is one of Switzerland's most respected contemporary writers, with three earlier novels, four collections of short stories, and various essays , poems, plays, and screenplays to his credit. ''The Ballad of Typhoid Mary'' is the first of his major works to be translated from German into English (and translated very well by Joel Agee, the son of writer James Agee and himself author of ''Twelve Years: An American Boyhood in East Germany,'' published in 1981).

A recent interview with Federspiel revealed an engagingly unpretentious, even shy man, whose fundamentally pessimistic view of life is strongly tinged with wry, ironic humor and a deep compassion for the human condition. In the character of Typhoid Mary, Federspiel has found a subject whose bizarre tragedy aptly suits his vision of the world.

Although based on the outlines of an actual case history, his ''Typhoid Mary'' is largely a work of fiction. The real Mary Mallon, believed to have been an Irish immigrant, had worked as a cook for a series of well-to-do New York families until, in 1907, she was discovered to be a typhoid carrier whose cooking had infected countless victims with the disease, to which she herself was immune. When she was determined to continue cooking for people - despite severe warnings from medical authorities and the police - she was kept in almost total isolation until her death in 1938.

Federspiel first heard of Typhoid Mary while visiting New York in 1980. He was told that her tale was a myth; but when his research revealed that her story was true, he became virtually obsessed with its strangeness and the irony of its moral implications. What clearer parable could there be for the philosophy to which he already subscribed: that there is ultimately no order and no mercy in the universe, but that one woman, by a cruel quirk of fate, could innocently cause the deaths of hundreds of unsuspecting victims simply because she loved to cook?

Federspiel, however, does much more than document the grisly details. He makes us care about his tragic young heroine, filling in with dramatic, salacious, and poignant detail Mary's early years as a teen-age immigrant (of which nothing is actually known). He felt such empathy for Mary that he made her Swiss (like himself) and saw her as a victim of circumstance, wanting only to find a husband, raise a family, and earn her living as a cook, totally ignorant of the effects of her cooking.

If readers are shocked at such goings-on, that is precisely what Federspiel intends. He may be trying to wake us up to the dangerous nature of ignorance. Or he may be simply letting out a wail of protest against the tragic ironies of such a story.

But what I found most intriguing was Federspiel's pungent, totally unromanticized portrait of 19th-century America. Like Dickens in ''Martin Chuzzlewit,'' he seems positively to delight in pointing out the poverty, crudeness, violence, and hypocrisy in what the immigrants believed was the Promised Land.

Chances are we'll be hearing from J. F. Federspiel again before long. He says he thinks of New York as his second home, and his publishers are eagerly examining his other works with a view to future publications. It will be interesting to see what they serve up next.