Anyone who has helped shape or has shared the vitality of Chicago`s theater scene will find in the premiere of this season`s ”American Masters” one of the most compelling, fascinating, inspiring and invigorating documentaries you will ever see.

The series premieres at 9 p.m. Monday on WTTW-Ch. 11 with ”Broadway Dreamers: The Legacy of the Group Theater,” a remarkable piece of work.

It is remarkable both for its subject-what has been called ”the bravest and single most significant experiment in the history of the American Theater”-and for the style in which it details the decade-long history of the Group Theater.

Using photographs, rare archival footage, feature film and newsreel clips, the program perfectly captures the times that spawned and fueled the Group Theater. But at its emotional core are a number of in-depth interviews with those who created and became members of this unique gang of theater artists.

Motivated by their feelings that the American theatrical scene of the late 1920s, specifically the Broadway scene, was conservative and old-fashioned, the Group formed in 1931 around an idealogical center comprised of Harold Clurman, Cheryl Crawford and Lee Strasberg. With the country in the grip of the Great Depression, these three began to recruit like-minded artists to their cause.

It was bold, unprecedented. They wanted to do nothing short of change the face of American theater. Using the then-new ensemble approach, they wanted to produce new American plays that not only mirrored but would stimulate, and even change, America.

They did not, most of the participants agree, always meet that lofty goal. But their passion, power and such plays as ”Awake and Sing,” ”Men in White” and ”Waiting For Lefty” did blaze across the Broadway landscape for a decade and, as the program details, left a legacy that touches the work and the spirit of anyone in theater.

Just the short list of Group Theater members reads like an America Theater Hall of Fame: Luther and Stella Adler, Franchot Tone, John Garfield, Elia Kazan, Ruth Nelson, Sanford Meisner and Clifford Odets, the actor spurred to playwrighting wizardry by his association with the Group.

Interviews with most of these grand characters are conducted by Joanne Woodward. They are incisive, evocative and moving. More than a few tears are shed, at such memories as that of the opening night of Odets` ”Waiting For Lefty,” when the cheers and applause built into a foot-stomping frenzy that threatened to literally bring down the theater`s balcony.

Internal conflicts, the lure of Hollywood and the determined uncommercial bent of the Group proved its eventual undoing. But what it did, the tone it set and the teachers it produced-Strasberg, Stella Adler, Bobby Lewis, Meisner-influenced and continue to touch the lives and the art of any person working in theater.

One leaves this program filled with admiration, knowledge and wonderful stories. For instance, there was the day that Clurman asked a young actress named Kate Hepburn to become a member of the Group.

”I told them, `I don`t want to be a member of any group. I want to be a great big star,` ” Hepburn recalls.

She got her wish, but as this exceptional programs shows, what a glorious and incredible time she missed.

`Marilyn MacKay`s Autograph`

There is nothing whatsoever confrontational about Marilyn MacKay and therein lies the strength and the weakness of ”Marilyn MacKay`s Autograph,” a new PBS syndicated program that is having a Monday through Thursday fling at 11:30 p.m. on WTTW-Ch. 11.

The Detroit-based interviewer will, at her worst, remind local viewers of Nancy Merrill, the short-lived entertainment reporter for WMAQ-Ch. 5. At her best, MacKay is an amiable and unthreatening companion.

Her cozy style flies in the face of many in that current crop of celebrity interviewers who behave like vultures picking over stars` bones. Her questions are generally expressions of a mind that is pleasantly inquisitive and relatively intelligent but stops just short of being probing.

The more a subject has been interviewed, the less likely he or she is to let their guard down long enough to spout things of interest. MacKay`s lineup this week (Luciano Pavarotti, Betty Friedan, Christie Hefner, Joe Sedelmaier) should display her capabilities. Then it will be up to the bosses at WTTW to determine whether this chit-chat show will become a permanent fixture in the fall.