BETWEEN THE BLACKOUT and the searing, mephitic air, it has seemed from this climate-controlled cube as if we might be fumbling our way toward doomsday and not all that amiably, either. But such thoughts weigh heavy in the head, causing ill humor, and lead pretty much to naught. Better to think a green though in a green shade; better to think, for example, about raising a place in the country, a fantasy a lot of people cherish and some, like Peter H. Matson, actually do something about.

"A few years ago," he begins this appealing, pleasurable chronicle of house-building, "I thought to find a place removed from the inffluences of the city, a simple place to be with my children on weekends, where vegetables would grow and water would come out of a well. Like many before me I soon discovered that what I wanted was a house like none I had ever seen, and that to realize it I would have to build it myself, with my own hands."

Of such dangerous epiphanies more smashed thumbs than Waldens are made, or even places in the country. Matson's book is subtitled "A Narrative on the Imperfect Art of Homesteading and the Value of Ignorance." It is a sort of latter-day dialogue and occasionally and argument with Henry David Thoreau, whom Matson calls the "Preacher of Walden" and accuses of stretching the truth a bit. And no doubt he did. I dealing with dreams, truth can be as elusive - and as vivid - as a mirage. In building a house, though, it is as plain as a chestnut crossbeam, and sometimes as hard to handle.

"Building a house was my oldest fantasy," Matson writes, "more familiar than sex: houses of blocks, of blankets, houses, built with walls of air and roofs of it-never-rains. But since I was 18, I have always been a tenant some place. Living in other people's houses I have never been home, nor had any idea I was missing something. To paraphrase Thoreau, I thought a house a prison in which I found myself oppressed and confined, not sheltered and protected . . ."

So Matson, on an initial investment of $12,000, bought a few acres on a Berkshire hillside in western Massachusetts and an old barn, which he planned to move to the site. "Now I find a place of earth and air, trees, bugs, brambles, waters, mud, lots of granite, a piece of planet that the White Man's Law says is mine. The joy realized is akin to the adolescent discovery of sexuality and no less complicated and all-pervasive. Or rather it is all very much the same thing: the discovery that we are - still - creatures of nature needing earth, air, privacy to sustain us, our drives and our perversions. The wreck of our Inner Cities is the negative testimonial."

Wielding a chain saw like a maniac artist, Matson cleared his site - altering nature to fit his plan - then backed away to see what he had wrought with his machine. "For the first time, I thought that in actual fact a house might finally rise from that patch, sheltering, comforting, resisting wind and rain and time." The foundation was poured, the barn moved, the house finally built, to his own specifications, mostly with his own hands, and with a copy of Ramsey and Sleeper's Architectural Graphic Standards for technical assistance. Although his was not a rich man's operation, neither was money the major problem. "The two essentials in short supply are time and patience, and if I could just find the one," Matson writes, "I could do without the other."

A Place in the Country is neither a how-to-do-it manual or a how-I-did-it hymm; it is, actually, more of a thoughtful why-I-did-it by a successful New York literary agent whose customary trade is plied in considerable part over expensive lunches at places like the Italian Pavilion, where real money is put down on seductive dreams. Literary agents - not to mention book publishers and reviewers as well - have much in common with the rural real estate agent Matson describes in his book: "Wait till you see this,' said the agent in the tones of a snake-oil salesman hawking Health Everlasting for only 99 cents (and satisfaction guaranteed in this life or the next)." When you deal in such dreams, it's reassuring to get back to reality now and then; maybe that's why Peter Matson built his house.

Whatever the reason, I'm glad he did it, and I'm glad he wrote about it, too. I only wish there were more illustrations, although perhaps his descriptions are enough; the reality might lack the enchantment of the dream he describes: "And up the path, sitting a little awkwardly on the brow of the hill, there is a house. Is it too tall from this angle, do you think?heavy with glass and a dormer where no dormer should be? The cedar siding has weathered to a light brown, greyer around the doorstep where the rain drives into it. But some of the trim is almost new, giving away - if you hadn't noticed before - that this is certainly an amateur-built house."