Testing the Current, by William McPherson (Washington Square/Pocket Books, $4.95). It's 1939, the last year of peace. Small-town life is seen from beneath the folds of a heavy tablecloth, through a frost- rimmed window, across the waters of a lake, recorded by the watchful eyes of 8-year-old Tommy MacAllister. The development is gradual, the picture intricately detailed, of what one reviewer called "that mysterious unwritten-about world," the inner life of a maturing child.

Mr. Britling Sees It Through, by H.G. Wells (Hogarth Press, distributed by Merrimack Publisher's Circle, $6.95). For some critics this is the English novel about World War I. For the author it was the book that turned the tide of literary ill-fortune -- including some novels rejected for being too frank and others criticized by the sharp-penned likes of Rebecca West for being too old-maidish -- which had swelled to career-threatening proportions. Like much of Wells' non-science fiction, it is a book whose neglect and unavailability have been puzzling. Wells' social novels are briskly paced, funny, and perceptive. He was one of his era's finest literary portraitists, Mr. Britling one of his most memorable subjects.

Chikara!, by Robert Skimin (Pinnacle, $3.95). From destitution to a computer fortune -- so fares the Japanese House of Hoshi. The novel's focus shifts among those who stayed home, those who emigrated to California, and those who roved back and forth between the two locales. Its driving forces are ambition, racial discrimination, the Japanese sense that family promises must be kept, and the desire of women for freedom. The title means "strength" or "talent" and might well be applied to author Skimin's ability to make a long, complex tale seem grippingly short. NONFICTION

Inuit, by Ulli Steltzer (University of Chicago Press, $22.50). From places with the exotic names of Igloolik, Gjoa Haven, Bay Chimo and Paulatuk, Ulli Steltzer brings us a rare record of a culture -- that of the Inuit Eskimos in Canada's Arctic. Their preserve stretches from Labrador to the Yukon, and their way of life combines ancient customs -- like leaving messages on rocks to tell fellow fishermen of good catches -- and modern methods like high technology drilling for oil. Steltzer has an unfailing eye for the telling detail of daily life. Her photographs, many taken under trying climatic conditions, speak eloquently of a special kind of culture.

How a Woman Ages: Growing Older -- What to Expect and What You Can Do About It, by Robin Marantz Henig (Ballantine, $7.95). There is good news and bad in this hefty trade paperback. The good news is that aging need not mean debility or decline; the bad is that aging does mean change. Robin Henig, one of the clearest expository writers to tackle medical and scientific topics for the layman (she's written books about premature infants and senility), seeks to demythologize aging, specifically female aging, by detailing the facts of its process, then explaining how to cope. Her message, loud and clear, is two-fold: clean living makes aging easier, and a positive attitude is essential to well-being. So, suck in the tummy, stand up straight, drink your milk, and, above all, keep walking.

The Book of Whales, by Richard Ellis (Knopf, $16.95). An outsized book about an outsized subject by one of those enviable naturalists who are also first- rate painters. (Among other distinctions, Ellis has long been an American delegate to the International Whaling Commission.) The text distills what is known about the greatest cetaceans. It is nice to learn, for example, that the narwhal's tusk is actually an elongated tooth, asymmetrically located on the left side of the skull and spiraling counterclockwise to the tip. The drawings and paintings depict the beasts in all their warty glory, including the barnacles that fasten themselves onto older specimens.

People of the Ice Whale, by David Boeri (Harvest/HBJ, $6.95). Environmental conflicts can be easy to judge when they pit a quivering creature against a greedy developer. But what if the exploiting party is itself threatened, its ages-old way of life at the mercy of civilization's intrusiveness? Such is the complex case of the bowhead whales and the Beaufort Sea and Bering Strait Eskimos. Boeri's controversial conclusion is that the various federal, state, and local bureaucracies should withdraw and allow the Eskimos themselves to decide whether to retain or abandon their whalebound culture -- even though "the bowhead's survival may well be on the line." FANTASY AND SCIENCE FICTION

Hell House, by Richard Matheson (Warner, $2.95). In the annals of contemporary macabre fiction, Richard Matheson holds an honored place as the author of several classic works that have become movies: "Duel," I Am Legend, >The Shrinking Man, and Hell House. This last is certainly one of the two or three most disturbing treatments of the haunted house theme (rivalled by Shirley Jackson's The Haunting of Hill House) and it is good to have it again available to scare the daylights out of a new generation of readers.

Flight From Neveryon, by Samuel R. Delany (Bantam, $3.95). Among science fiction and fantasy writers none is more intellectually ambitious than Samuel Delany. In the past year he has already brought out Stars in My Pockets Like Grains of Sand -- a major novel about information networks, sexuality, and social change -- and an equally important collection of theoretical essays, Starboard Wine. In this book, the last in a threesome about Nevriches two fantasy tales of a magical city with a number of footnotes relating fictional events to everyday life in New York City, the result something like Nabokov's Pale Fire -- but more ponderous and personal. At least one egregious error mars the book: the misnaming of a favorite author as Basil instead of Guy Davenport.