CHRISTO, this is one hunk of a book! !

Shall we begin with a true confession? I read this 694 page document of an extraordinary art project while lying in bed and fortunately survived with nothing more than a sore arm. Fall asleep with this baby, and you may never wake up, victim of a collapsed chest.

But more to the point: lovers of codices will find Christo: Running Fence a bargain at $200, or roughly $20 a pound; others may find it, well, a bit heavy.

What we have here is a record of Bulgarian-born artist Christo Javacheff's four-year odyssey: building a 25-mile fence across Marin and Sonoma counties in California.

This may sound a bit odd, until you realize that Christo's work deals with, in his words, "the monumental and transient." In the past this has meant wrapping in fabric ings like gigantic balloons (the 1968 "5,600 Cubic Meter Package," for example, that wound up being a 280-foot-long plastic sausage), the Bern Kunsthalle, Chicago's Museum of Contemporary Art and - most recently - 104,836 square feet of pathways in a Kansas City park (documented in Christo: Wrapped Walk Ways, Abrams, $20; paperback $12.50.)

Indeed, the running fence was both monumental and transient - costing about $3 million - all raised by the artist through the sale of his drawings - and standing for exactly 14 days. The project may well have been the most colossal piece of conceptual anything ever created, certainly epitomizing Tom Wolfe's dictum that believing is seeing: four years of work culminating in one two-week, albeit 25-mile, fence. Some called it art; others "a gargantuan roll of toilet paper unfurled across pleasant dairy lands."

Virtually everything about that fence is recorded here: the origial drawings, the 17 public hearings, the work of nine lawyers, the contracts with the 59 property owners involved, the $130,000 invoices from the J.P. Stevens Co. for 165,000 yards of white nylon fabric, the environmental impact statement, public notices announcing the hearings, 1,000 postcards and letters concerning the project, even a piece of the same material the fence was made from.

As with the work itself, the book "suggests a consistency that borders on obsession," as Calvin Tomkins wrote in his New Yorker essay on the project, which is reprinted in the gbok, along with a rather free-wheeling account of the construction by Elizabeth Whitney that originally appeared in the Tomales Bay Times. These are the only two narrative pieces in the volume, taking up less than 25 pages. The remainder consists of engineering sketches, correspondence, the entire 341 pages of the environmental impact statement and hundreds of photographs by Gianfranco Gorgoni.

Only in its last 200 pages does the book get at all fascinating, as the 2,100 68-by-18 foot panels are attached to their 13,000 steel anchors with 312,000 eyehooks. The documentation and numbers dissolve as the contrast of the fence becomes outlined clearly against the northern Caliornia farmland and beach front. Gorgoni's photos capture thsoe oddly magic 14 days along the fence route, when viewers could gaze across pastures and beachers to find the landscape traversed by a thin, white plane that seemed to stretch to infinity, disappearing only into the Pacific Ocean.

And then, on September 24, 1976, the whole thing was disassembled, the individual components given to the owners of the land the fence crossed. Not mentioned in the book, the remnants have evolved into blouses, canopies, indoor ski slopes, murals - and even a bird-droppings catcher hung in a barn. One rancher sold sections of the fence to tourists and art collectors for $100.

Whether one of those $100 sections or this $200 book is a better investment is a tough question. The fence had in effect, an edition of 2,100 sections; there are 2,159 signed copies of the book. The fabric can be shaped into several practical items; the book is filled with mostly impractical information, although it contains a number of striking photographs.

The merely curious would probably be better off with the original catalog of the Running Fence Project, published in 1977 by Abrams for $10. Unfortunately the 128 page paperback is out of print. Only 5,000 were made, but the company is considering a second edition.

Meanwhile, it's 200 big ones, or shut up.

Or, get involved in Christo's three latest projects, wrapping: Paris' Pont Neuf; Berlin's Reichstag; and the monument to Columbus in the Barcelona harbor.

There are sure to be some scraps left over. CAPTION: Picture, no caption, by Wolfgang Volz from "The Running Fence Project" (Abrams)