The tastemaker behind the McMillen style

Eleanor McMillen Brown has just completed six decades in the interior decorating business in New York, and is still as enthralled with the world of design and beautiful things as she was in 1924, when, with $15,000, she opened the doors of McMillen Inc.

At 93, she is still active in the management of her prestigious firm and consults regularly with Betty Sherrill, president, and other staff members on the creative work they have in process. The firm's roster of top-drawer clients includes Mr. and Mrs. Henry Ford, Mr. and Mrs. Henry Cabot Lodge, Mrs. Marjorie Merriweather Post, Mr. and Mrs. Douglas Dillon, and hundreds of others who, over the years, have sought the well-bred, fine-quality look of a McMillen interior.

Now these rich years of accomplishment have been chronicled by author Erica Brown (not related) and amply illustrated by more than 500 photographs of interiors in a new volume called ''60 Years of Interior Design: The World of McMillen'' (New York, Viking Press, $50). It is an important compilation of illustrations, information, and commentary and will be an especially useful reference book for design schools and libraries.

Readers as a whole will be fascinated with Eleanor McMillen Brown and her remarkable career, and with the insights the book provides about this particularly important coming-of-age period in American design history. It is a record of one trend-setting firm's imprint and impact on numerous homes, hotels, clubs (including the Cosmopolitan Club in New York), corporate offices, historic landmark houses, US embassies, Blair House (the official guest quarters in Washington, D.C.), and even the White House itself.

Mrs. Brown has presided over what was probably the first professional full-service interior decorating firm in America. She trained at the New York School of Fine and Applied Arts, and quickly proved that she could not only put together stylish interiors but also had a clear head for business. ''Until Eleanor came along,'' Albert Hadley, one of the firm's alumni, is quoted as saying, ''the lady decorators such as Elsie de Wolfe, Ruby Ross Wood, and Rose Cumming were doing pretty, comfy houses without much direction or point of view. It was her strong design consciousness that made McMillen different. She had an educated eye, an educated mind, and she worked relentlessly to achieve perfection and beauty. Also, I think Eleanor was ahead of her time in her sense of adventure in bringing things together that were totally compatible but not of the same period.''

Although the design scope covered in the book ranges from traditional periods to Bauhaus, art deco, streamlined Moderne, and contemporary eclecticism, Mrs. Brown herself prefers period furnishings - Louis XVI, Directoire, and 18 th-century Italian furniture, classically styled pieces in black and mahogany, and Egyptian Revival furniture. She favors School of Paris paintings, late Impressionists, and flower paintings of all sorts.

Eleanor Brown has lived in the same duplex apartment in Manhattan since 1928, and its decoration has remained essentially the same over the years.

''I'm perfectly happy with what I have,'' she says. ''It functions and it's very pretty. If you get it right the first time there is no need to change.'' Walls are repainted about every 20 years in the same color each time - yellow (''It's a good city color - it's cheerful'') - punctuated by white pilasters. She has her seating pieces reupholstered occasionally to bring them up to date, and adds or subtracts a few antique pieces from time to time.

Yet the rooms remain basically unchanged, because, she says, ''I like simplicity and I believe in restraint. And above all, I feel there has to be harmony - of proportion, line, color, and feeling.'' She says the most important element in decorating is the relationship between objects - in size, form, texture, color, and meaning. ''None of these is in good taste in itself, but only in relationship to where it has been placed and what purpose it is to serve.'' Her own home underscores a McMillen theory that good, finely detailed, and ''finished'' decorating lasts a long time.

Asked her definition of good taste, she replies: ''Taste is relative, but to be positive and vital it must respect the past, accept the present, and look forward with enthusiasm to the future. The contemporary eye combines objects and materials of the present with objects and materials from the past. Active, positive taste demands a constantly fresh appraisal of familiar forms, holding on to those things that add quality, beauty, and pleasure to one's life, and disposing of superficial impediments.''

Mrs. Brown is sometimes referred to as a ''legendary'' figure, yet her staff of 30 designers, architects, and assistants thinks of her as a very present and constant friend and mentor. Walter Hoving, former chairman of Tiffany & Co., refers to her as a ''serious, down-to-earth woman who believes emphatically in perfection.''

Her influence on several generations of young decorators has been enormous. Her staff has always called her ''the boss,'' and her word, though it is always soft and never harsh, is the last word. The new book reveals many of her most basic design principles and shows that she has never let down her own standards.

When she reached 60, Mrs. Brown thought for a fleeting moment about retiring. But she detected a sudden growth of discernment and taste on the part of the public, so she decided to stay on awhile. Now, 33 years later, she is glad she did. She considers herself partly retired, but she is in her office nearly every day.