EIGHT YEARS after the release of its landmark "Smithsonian Collection of Classic Jazz," that venerable institution is about to unveil another monumental project, the eight-record "Smithsonian Collection of Classic Country Music." Three years in the making, and with 143 selections spanning six decades from 1922 to 1975, "Classic Country Music" reflects the phenomenal surge of interest in that genre over the last five years. Country music now accounts for close to 20 percent of record and tape sales, while more radio stations are switching to country formats than to any other. And as the music achieves new popularity, there has been a concurrent interest in its historic roots.

The Smithsonian collection kicks off with Eck Robertson's fiddle variations on Sally Gooden" in 1922 and ends with Willie Nelson's "Blue Eyes Crying in the Rain" in the 1975; in between, one meets names as familiar as Jimmie Rodgers, Hank Williams, Ernest Tubb, Roy Acuff and Merle Haggard and as unfamiliar as Montana Slim, Riley Puckett, Milton Brown and His Brownies and Martha Carson. The album moves chronologically, the exceptions being the bluegrass album and a study of Southeast and Southwest styles in the '30s.

The idea for "Country Music" originated three years ago and was spurred on by the success of the "Classic Jazz Collection" (200,000 sets sold) and the nine-record Bach set. The selection of songs was made by country-music scholar Bill Malone, who also wrote the 64-page booklet that accompanies the boxed set. "I wrote in to get some literature and they wrote back to ask me if I was the Bill Malone who wrote 'Country Music USA,'" Malone recalls. "They'd been thinking about me and wondered where I was."

Malone gave the Smithsonian an outline, a framework that he insists "should not be considered the 143 top songs or a country hit parade. My intention was to tell the story of country music as it evolved over a 60-year period from the '20s, encompassing the major styles and artists." Malone's informed and impassioned booklet traces the development of country music from its early days of string bands and strong regional styles to its homogenization in the '50s and the many variations on country music that have emerged over the years.

From Malone's list, production coordinator Bill Bennett and assistant producers Jane Sapp and J. R. Taylor set about acquiring the necessary rights and permissions and then hunting down acceptable copies of the older recordings. Ultimately, 17 companies were involved, many of them in caretaker status for long-disappeared labels like Okeh, Bluebird and Vocalion. More than half the selections on "Classic Country Music" have not been commercially available for a long time; 23 have never appeared in album form.

A major problem, according to Taylor, "was finding the record, or finding it in a masterable condition. With a lot of the older and less commercially viable material, sometimes even the majors don't have a copy or a tape. When the material is 50 years old, and some of it was pressed only in the hundreds of copies for regional distribution and was played on fairly beat-up equipment and was loved to death, you take what you can get."

The older recordings came from country music's two major archives, the Country Music Foundation in Nashville and the John Edwards Memorial Foundation in Los Angeles. Some material was also provided by two of the country's most avid collectors, Joe Boussard of Frederick and Dick Spottswood of the Library of Congress. The next stop for the older material was with master technician Jack Towers, who last year won a Grammy for restoring some tones of horrendous quality for the album "Duke Ellington in Fargo, ND, in 1940." Towers is one of the primary people involved in the restoration of old records on tape, to the extent that an admiring Taylor says he can "correct the old 80 rpm turntable that Brunswick had as their cutting rig for a while, bringing it all down and making it sound like human beings at work."

Many of the selections on the eight-album set predate the era of stereo sound, and Towers has done a commendable job of eliminating surface noise (on the older selections), cleaning up the sound quality without sacrificing authenticity. "It was a chore to get them quieted down," Towers admits. In the era of 78s, the recording speeds could vary from 75 to 82 rpms, which could change the pitch considerably. Towers spent anywhere from 20 minutes to three days "slugging away" at each selection. As the technology evolved, his work became easier. By the time the '50s material rolled around, "I was glad to get there. It was a breeze after that."

Cynthia Hightower, director of the Smithsonian's Recordings Projects, points out that the institution "stumbled into the record business" when it was first organized in 1973. "Now we're very serious about it." She expects first-year sales on the country set to reach somewhere between 30,000 and 50,000, spurred by a direct-mail campaign to the Smithsonian's 1.8 million associate members. For the first time, the Smithsonian will also use outside mailing lists and magazine advertising to solicit sales for "Classic Country Music." "It's one of the things we negotiated very strongly," Hightower says; Smithsonian records are otherwise available only by mail or in Smithsonian shops.

Like the "Classic Jazz" project, "Classic Country Music" will be an umbrella project for other single and double-album projects in the country genre. And, says Bennett, "what was most impressive to me was the acceptance of the 'Classic Jazz' set in educational circles. It has become a standard textbook tool in the teaching of jazz because it is a very compact and concise perspective of the field -- very much the kind of thing we're trying to do here -- touching on most of the major styles and the major performers within the idiom."

Although small independent companies like Rounder, Arhoolie, County and Folkways have been releasing archival material for years, the Smithsonian collection is the first comprehensive historical survey of country music. Time Life is reportedly testing its own collection, and the Franklin Mint has just started to advertise its 100-volume classics of country music country continuity series with the backing of the Country Music Foundation.

The Smithsonian is well aware of its competition, but insists that "Classic Country Music" reflects the institution's historic imperative as a living, breathing archive. "We're trying to give an overview from which you can decide what you like," says Bennett. "From there, you can follow your own nose deeper and deeper into the country music tradition."