The Boat of Longing, by O.E. Rolvaag (Minnesota Historical Society Press, St. Paul, Minnesota 55101, $7.95). Rolvaag, the immigrant Norwegian writer whose masterpiece is Giants in the Earth, called this his favorite among his novels. Published in 1921, it is a haunting story that brings to mind Bob Dylan's ballad, "I Pity the Poor Immigrant." The newcomer in question is Nils Vaag, and the slender plot concerns his attempts to conquer the sense of isolation that plagues his early months in the United States. In addition to the light it casts upon the immigrant experience, the novel illuminates the settlement of the Upper Midwest.

In a Pig's Eye, by Karl Schwenke (Chelsea Green, $8.50). For fans of E.B. White's Wilbur and other literary pigs, this collection of stories -- all concerning the porcine and all set in rural New England -- is a treat. They tell of people, mostly conditioned by city living, who've moved to the country and find themselves dealing no longer with bucolic myth but with the harsh realities of "homesteading." NONFICTION

Inner Light: The Shaker Legacy, photographs by Linda Butler, text by June Sprigg (Knopf, $19.95; hardcover, $29.95). The Shakers designed their buildings and furnishings to evoke the spirit of God. They succeeded in their intent, and their legacy -- the simplicity and beauty, the light and perfectly proportioned space -- reproduced here in stunning photographs, continues to give us pleasure.

Nothing More Agreeable: Music in George Washington's Family, by Judith S. Britt (Mount Vernon Ladies' Association of the Union, $8.95). Music in the life of the Father of His Country, with many beautifully illustrations.

Ireland: A Concise History From the Twelfth Century to the Present Day, by Paul Johnson (Academy Chicago, $6.95). The author is the former editor of the New Statesman and the author of Modern Times, an elegantly written, provocative retelling of 20th-century history by a died-in-the-wool conservative. Englishmen venture into Irish politics at their peril, but Johnson's sympathetic yet tough-minded history seems founded on solid scholarship and is graced by first-class writing. It will, of course, not please zealots.

The Plug-In Drug, by Marie Winn (Penguin, $6.95). According to Marie Winn, it doesn't matter how high the quality, watching too much television isn't good for children. As a passive activity, television watching tends to deaden the senses and the ambitions. And children become addicted to the "television trance" just as druggies do to their highs.

Earthly Pleasures: Tales from a Biologist's Garden and Field Days: Journal of an Itinerant Biologist, by Roger B. Swain (Penguin, $6.95 each). Two volumes of nature essays by the science editor of Horticulture magazine. Swain tackles some of the glamourous ecological controversies -- gypsy moth infestations, water pollution, destruction of tropical rainforests -- but his forte is musing about the mundane and lesser-known. He devotes one essay to duckweed, another to plant life along the railroads of St. Lous, which has "the second largest railroad network in the United States." Another piece, on fertilizer, is called "Dung Ho"; quite properly, it begins with a depiction of the World Champion Buffalo Chip Throwing Contest in Chadron, Nebraska.

D.W. Griffith: An American Life, by Richard Schickel (Touchstone, $12.95). This long and important biography explores in full the life of Griffith, the first American film maker to realize that movies were an art form. The virtual inventor of the feature- length film, he made such legendary films as The Birth of a Nation and Intolerance. As this life by the movie critic of Time makes clear, he was a driven man, consumed by ambition. MYSTERY AND SUSPENSE

Cogan's Trade, by George V. Higgins (Carroll & Graf, $3.50), and A Choice of Enemies, by George V. Higgins (Carroll & Graf, $3.50). Here we have two novels, one early and one late, by a deservedly admired practitioner of suspense fiction who more often than not manages to rise considerably above his genre. Both are set, as all of Higgins' best fiction is, in Boston, though the Bostonian worlds they inhabit are at least superficially different. Cogan's Trade (1974) is his third novel; like the first two, it is about a small-time crook, in this case an "enforcer," who practices the art of survival with impressive skill and world-weariness. A Choice of Enemies (1983), his 11th, is about a notably cynical speaker of the Massachusetts House of Representatives and the equally cynical circles he inhabits. Each book is in its own way aovel of manners, each reveals an impressive knowledge of Boston folkways, and each is exceedingly funny.

Too Many Cousins, by Douglas G. Browne (Dover, $3.95). This reprint of a 1946 detective novel features Harvey Tuke, a sleuth of satanic appearance and brilliant mind, working on a case involving the inheritance of a family fortune. When is there an excess of cousins? Why, when each surviving one is entitled to an equal share in the estate: it's a situation tailor-made for multiple murder and the elimination of false leads. The book is slightly mannered in style but strong on applied ratiocination.

Switch, by William Bayer (Signet, $3.95). Two extraordinary events happen to veteran New York City police detective Frank Janek on the same day. He and a woman 15 years his junior fall in love; he is assigned a case involving two decapitated women whose heads were switched before discovery by the police. As the love affair progresses, the case deepens and ramifies until it encompasses a stolen-car operation, prostitution, some of Janek's fellow officers, and a twisted film-maker. A hugely entertaining police procedural from the Edgar-winning author of Peregrine.

Sunday Hangman and Snake by James McClure (Pantheon, $2.95 each). James McClure sets his mysteries in South Africa, which gives them an added fillup. His detective Lt. Trom Kramer and his Bantu assistant Mickey Zondi, not only solve bizarre crimes, but their milieu gives McClure ample opportunity to profile South African life. These are not only mysteries, and finely drawn social documents. And the writing is supurb!