The Long Valley, by John Steinbeck (Penguin, $3.95). Except, perhaps, for The Grapes of Wrath, John Steinbeck's reputation will rest on his shorter works -- the novellas Tortilla Flat and Of Mice and Men and the stories collected in this volume. Among them are classics like "The Snake" and "The Chrysanthemums" and the three parts of "The Red Pony" proper, along with the related story, "The Leader of the People." Made into a film with a haunting score by Aaron Copeland, "The Red Pony" is the story of Jody Tiflin, a ranch boy whose life takes on new meaning when he is given the eponymous pony as a pet, and Billy Buck, the ranch hand whose apparent infallibility dies with the pony itself. Set in Steinbeck's home turf, the Salinas Valley of California, these stories manifest his chiseled style and extraordinary affinity with animals.

Other Men's Daughters, by Richard Stern (Arbor House, $5.95). Middle-aged professor meets lovely summer student: a familiar story, to be sure, but Richard Stern imbues it with rare tenderness and subtlety in this highly accomplished novel. The depth of feeling between the two lovers is made palpable, as is the terrible sense of guilt and isolation the older man feels as he separates from his wife and becomes -- in his own mind, if not in actuality -- a pariah among his friends. Stern is an uncommonly gifted observer of the pleasures and tensions of domestic life. NONFICTION

The Complete Graphic Works of William Blake, by David Bindman, assisted by Deirdre Toomey (Thames and Hudson, $35). The graphic work of William Blake is almost overwhelming in its quantity, its strangeness, and its strength. This book, first published in hardcover eight years ago, is a stunning tribute to that powerful poet and artist. Over 800 illustrations are included, works from Songs of Experience and Songs of Innocence, the Book of Thel and Jerusalem, among others. A book to be savored slowly.

Secrecy and Democracy: The CIA in Transition, by Stansfield Turner (Harper/Perennial Library, $7.95). In February 1977 Admiral Turner was asked by his Annapolis classmate Jimmy Carter to be director of central intelligence. His personal memoir of his four years in that almost legendary job is remarkable for its candid discussion of the strengths and weaknesses of the nation's supersecret spy agency. Turner reveals as no other person could the internal workings of the agency in a time of change, asserts the necessity for espionage in the modern world and surveys the dangers of extreme secrecy to American democracy. The result is an extraordinary primer on the art of intelligence.

Space A: '86-'87, edited by Karen Davis (Connie Gibson Wehrman Connor Enterprises for Military Travel News, P.O. Box 9, Oakton, Va. 22124). This is the indispensable guide for active, reserve and retired military personnel and their families to flights on government aircraft on a "space available" basis.

The National Parks, by Freeman Tilden, edited by Paul Scullery (Knopf, $16.95). One of the pleasures of perusing this revised classic is to find William Penn Mott, director of the National Park Service, hinting in his preface at the advent of new national parks -- notably in the Tallgrass Prairie region of Kansas and the Great Basin region of Nevada. Only a few years ago, mention of parks-to-come would have been anathema to budget-cutters and ideologues railing against federal ownership of land. The book itself is a comprehensive guide to the national parks plus areas falling into all sorts of other national categories: monuments, recreation areas, wild and scenic rivers, battlefields, historic sites, and so on. (The sole criterion for inclusion is that they be managed by the Park Service.) Though the truly curious will want to supplement the book with more detailed guides to the individual parks they visit, the Freeman-Scullery collaboration cannot be beat for an overview of the system that has been imitated all over the world.

Writing Culture: The Poetics and Politics of Ethnography, edited by James Clifford and George E. Marcus (University of California Press, $9.95). The all-inclusiveness of anthropology -- of which ethnography, the study of specific cultures, is a branch -- is demonstrated forcefully by the variegated entries in this book's bibliography. These range from Samuel Taylor Coleridge's Miscellaneous Criticism to Margaret Mead's classic Coming of Age in Samoa to Milan Kundera's article, ''The Tragedy of Central Europe." The product of a 1984 conference in Santa Fe, this volume sets out to answer the question why ethnography is now suspect, more particularly why anthropologists seem to have lost confidence in their ability to sum up other cultures with some claim to attaining objective truth. The answer formulated by anthropologists steeped in deconstructionism and post-modernist literature lies in acceptance of the reality that "ethnographic truths are . . . inherently partial" -- much, one supposes, like the rest of human knowledge.

Sea of Slaughter, by Farley Mowat (Bantam, $9.95). Farley Mowat, the great Canadian celebrator of vanished and vanishing ways of life -- Never Cry Wolf, The People of the Deer -- considers this to be his most important book: a comprehensive indictment of mostly Canadian and U.S. policies that have led to the drastic reduction of wildlife along the Northeastern seaboard. Among the creatures so jeopardized is the black bear, against which, Mowat writes, no one has ever been been able to establish a case "as a species inimical to human enterprise." Nonetheless, the bears are extinct on Prince Edward Island and greatly reduced everywhere else, thanks in no small part to a Canadian recommendation that hunters be allowed to kill 30,000 of them a year. For his final chapter he saves the seals -- a modest success story, in that the opponents of their slaughter "are slowly gaining ground."

Road to Tara: The Life of Margaret Mitchell, by Anne Edwards (Dell Laurel, $4.95). Back in the 1930s a young Atlanta journalist wrote a long dramatic novel about a spirited girl named Pansy O'Hara who lived at an ante-bellum plantation named Fontenoy Hall; the manuscript was shipped off to Macmillan, which accepted it with enthusiasm and did some minor tinkering -- Pansy became Scarlett, Fontenoy was turned into Tara. The rest is history, as recounted by Anne Edwards in this well-documented biography of Margaret Mitchell, the woman who wrote Gone With the Wind but got precious little pleasure from the celebrity it brought her. Edwards depicts Mitchell as a victim of the pressures fame exacts, one who was far less happy as an international figure than she had been more than a decade earlier as a reporter and columnist for The Atlanta Journal. This year is the 50th anniversary of the novel's publication; the reissue of Edwards' biography is one of several events marking the occasion.

Alex: The Life of a Child, by Frank Deford (Signet, $2.95). This short, painful book is the story of the courageous but ultimately unsuccessful battle against cystic fibrosis by its author's daughter, who died in 1980 at the age of 8; a dramatic adaptation of the book was recently broadcast on ABC television. The tale has all the ingredients of sentimentality and pathos, but Deford keeps them under control; he writes about his daughter's illness with humor, when it is called for, and with unstinting admiration for her character and determination. Deford is a widely respected writer for Sports Illustrated and the author of several other books.