Katherine Cooke spends much of her day talking about a man who has been dead for more than a century. Yesterday, she even called in a band and threw him a party.

Robert E. Lee, Cooke quickly tells you, was no ordinary southern gentleman. A brilliant military strategist, he was the only man offered command of both opposing armies in a war. As a boy in Alexandria he carried his arthritic mother to her carriage, and as a West Point graduate he married Martha Washington's great-granddaughter. On Jan. 19, the Confederate general who denounced slavery as an evil would have celebrated his 181st birthday. So yesterday, one of his biggest fans gave a party in his honor.

Cooke, the director of Lee's historic childhood home in Alexandria, "lives and breathes" the general, according to a curator at the museum.

For 13 years, Cooke has worked at the historic home, giving tours, training its docents, overseeing its weddings and receptions, even doing its bookkeeping. All this, however, is only a hint at the energy and interests of 85-year-old Katherine Cooke.

She has assisted unwed mothers, led a Shakespeare club, taught piano and directed choirs. She has been a newspaper columnist and political activist. She is now working on a book on her family. For almost 70 years, she has worked at the polls on Election Day, rising at 4 a.m. to get to her station long before the first voter. Last week, she served as keynote speaker to a chapter of the American Association of Retired Persons. Her topic: "Retire? Who? Me?"

"The reason I can't retire is I'm too busy," she said last week in her apartment in Alexandria's Goodwin House. In a 1980 "Senior Scene" column published by the then-Alexandria Gazette, she wrote: "The important thing is not how old you are but how you are old."

With her white poufed hairdo and blue-rimmed glasses, she does not look like a dynamo. But a glimpse inside her cupboards tells more of her story.

On kitchen shelves others reserve for Uncle Ben's rice or Campbell's soup, Cooke stores scrapbooks, snapshots, slides and her writings from decades past. In her efficiency apartment, space is precious and history comes first.

Senior citizens "are just beginning to be recognized," she said. "Because there are so many of us, politicians are now coming around and listening."

She adds that people such as Katharine Hepburn, Bob Hope and Bette Davis help get the word out that fun is not just for the young.

Jenny Bruch, a coworker at the Lee home, said that Cooke "keeps the enthusiasm up" at the 607 Oronoco St. museum. "She keeps adding to the volunteer list; she has the personality that knows how to get people interested."

A noted speaker, Cooke is at ease addressing professional groups about history or aging, and she does it often. "She taught music, you know," Bruch said. "And I've often thought that's why she is such a good speaker {and} has such good delivery."

"She is so alive," said Charles S. Speed, a retired Department of Energy employee who is editing Cooke's book on her family. Never a typist, Cooke wrote the historical account in longhand.

Cooke developed her interest in Lee from her husband Paul, a Civil War buff. When he died in 1975 after 49 years of marriage, she moved from her home state of Oklahoma, where she had taught music in the public schools, to Alexandria, where her daughter lived. Within months, she was working Saturdays at the Lee home. "It filled a void," she said.

Melba Parks, a friend of Cooke's since the week she arrived from Oklahoma, said Cooke is a "pack rat and as stubborn as I am." Parks said Cooke sees herself a "chronicler" and "a link with the older generation."

Life has not always been easy for Cooke. One of her daughters died, her husband died just as they had started traveling, and she lost her great-grandchild to sudden infant death syndrome.

"I have had pretty hard knocks, but you have to accept things as they come," she said. "There is no reason to fall to pieces. To continue mourning and feeling sorry for yourself is selfish. The only thing to do is pick up the pieces and go on."

Parks said, "She is always ready to go. She told me that her husband said she was like Fido: Open the door and she is ready to go."

For 13 years Cooke has worked at the Boyhood Home of Robert E. Lee, and since 1980 she has been its director. During her tenure, the Old Town home was placed on the National Register of Historical Places.

The Confederate general lived there from ages 5 to 18, when he left for West Point. Even so, it was difficult to place the red brick house on the register because, just as George Washington has allegedly slept in many homes, many Virginians have claimed Robert E. Lee as a former resident of their abodes. Last year, 12,000 people visited the Alexandria home, which charges no admission.

Yesterday, Cooke wore her 19th-century costume at Lee's home as a string quartet performed for the birthday celebration. As visitors browsed through the home, Cooke found a welcome audience for her Lee stories.

"One of Lee's men was talking about Darwinism," she said, recalling a favorite. "You know, Darwinism was a current topic then, and the man said, 'We could have come from the monkeys, but not Lee. He came from God.' "