TREEHOUSES: The Art and Craft of Living Out on a Limb, <i> by Peter Nelson. (Houghton Mifflin: $35, cloth; $19.95, paper</i> ; <i> 128 pp.)</i>

How could Peter Nelson’s “Treehouses” fail to please? Its subject is immediately attractive, with its implications of escape and fantasy. Through text and evocative color photographs by Paul Rocheleau, the book urges: Build a dwelling high in the air, surrounded by leafy nature. Design your arboreal haven according to the dictates of your whimsy, construct it with your own hands, then reward yourself by sitting contemplative in your shelter, “annihilating all that’s made,” as Andrew Marvell once proposed, “to a green Thought in a green Shade.” Cannily, Nelson offers something for everyone: First there’s a little historical background on this maverick subdivision of architecture. Then there’s a substantial section on treehouses built by or for kids. A general how-to department segues into the real-life saga--call it “Pete and Charlie Build a Treehouse”--of how the author and a sidekick do it with considerable knowledge of carpentry and more than a little help from their friends. Oddly, a couple of the aeries Nelson features verge on the smug bourgeois comfort of banal grand houses. Most, though, are original and expressive, tailored to the available tree and fired by the individual--often idiosyncratic--imagination. They’re emblems of independence, a significant part of America’s mythic self-portrait. Aesthetically, the most memorable of the book’s examples are a pair of irregular shacks attached to two gaunt, forked redwoods, created by a man mourning the death of his son by drowning. Pieced together from driftwood and other cast-off lumber, jagged, splintered and weathered gray, they have a wild, haunting beauty. Children still play in them, climbing their spiral staircases into the sky, nearly a quarter-century after the tragedy that fostered their creation.