By Patricia Sellers

(FORTUNE Magazine) – IN 1985, Frances Lear walked away from her 28-year marriage to television producer Norman Lear. Norman ended up with a younger woman and Frances with a divorce settlement worth $112 million and a grand scheme for spending the riches. She would start a magazine ''to fill a need in women to have happier lives.'' Lear's, the magazine that emerged last February with an astounding 76 pages of advertising, about twice the norm for a premier issue, is a glossy celebration of the vitality, sensuousness, and attractiveness of women over 40. Recent issues have each been packed with up to 100 pages of ads for autos, cosmetics, fashions, and financial services. Circulation is 350,000 copies, more than that of Harper's Bazaar. Out of hurt and frustration, Frances Lear, 65, tapped into an expanding older female market: Some 40% of American women are over 40 now, and in 2000, 46% will be. Achieving her goal, says the editor-in-chief and sole owner, has brought her ''a sock in the ego.'' With no experience in publishing, Lear took 2 1/2 years getting her national magazine off the ground. And no wonder. A manic depressive who has been on lithium for the past 15 years, she admits, ''My illness makes me more volatile than many other people who are the heads of companies.'' Her bizarre style has caused numerous staffers to defect. Until two years ago she ran Lear's out of her palatial duplex in Manhattan's Ritz Towers, with her cook and butler -- and sometimes her trainer, hairdresser, and manicurist -- nearby. As she explains, ''I wanted to save money. It seemed the better way to do business.'' Former editors say she was given to changing quotes in articles -- which she denies -- and she once flew into a rage when an editor wanted to capitalize the word ''god.'' Lear considers herself intense, passionate, and emotional, qualities that stem from a need during childhood ''for security and recognition and accomplishment.'' At 17 she dropped out of school to work as a salesgirl. Twice-divorced at 33, she met Norman Lear, who took her to Hollywood, where he developed All in the Family and Maude. Much of her personality landed in the blunt, abrasive Maude. By 1993, Lear envisions an empire with ''two good magazines and one on the drawing board. I think I'll have a weekly TV show, where I interview interesting people -- not celebrities for the most part.'' She has talked to publishers about a joint venture but may have trouble finding a partner. Some were turned off by her manner at the American Magazine Conference last October when an audience member asked her about the difficulties of magazine startups. ''It ruined my sex life for a few weeks,'' she replied. Was that answer a mistake? No, she says. ''I said it because I found that section of the program rather dull.'' P. S.