Bette Davis battled studio bosses, husbands and rivals during her long acting career, establishing a tough persona in real life to match her enduring Hollywood image. She would need all that strength when she faced illness in her final years, knowing that she could achieve a dark victory by meeting death on her terms.

Her personal assistant during much of that time, Kathryn Sermak, depicts a lioness in winter in her memoir, “Miss D & Me: Life With the Invincible Bette Davis.” The actress, in her 70s, still showed some bite in dealing with family feuds and the demands of stardom even as she suffered from cancer and a stroke.

Davis (1908-89) found solace in activity, especially acting. “People will leave you,” she told Sermak more than once, “but your work will always stand by you.” She wrote another book and, amazingly, appeared on camera a few more times, most notably for “The Whales of August” in 1987.

Sermak had come into Davis’ life in 1979, a 22-year-old ingenue hired for the summer who was to learn how an aging movie star lived — this particular movie star, anyway. Davis accommodated her celebrity by pleasing fans and shrugging off criticism. When a tabloid featured an unflattering photograph with the headline “Bette Davis doesn’t give a damn how she looks!” the two-time Oscar winner advised her assistant, “Remember that it is always the best food that the birds pick at.”

Davis had her way of doing things. In a hotel room she would re-arrange the furniture and add personal photos to the decor. She spent hours trimming shrubbery around a rented house to make it just so. The mercurial Miss D also decided to play Pygmalion, grooming Sermak to become a young lady with the poise and discretion befitting her position.

That meant learning how to dress appropriately, project her voice, choose the right fork at meals and even change the spelling of her first name to make it more distinctive. Miss D’s criticism hurt at times, yet Sermak realized that graduating from the Bette Davis finishing school had its advantages for a woman of her generation. She also learned a lot about the movie business.

Life on Davis’ terms included her trademark cigarettes; it’s hard to imagine her without a curl of smoke in the air. During a fire drill at a hotel she sent Sermak back to their room for her cigarettes. They were bound to kill her one way or another. Davis continued smoking after her cancer surgery and stroke — and after she suffered second-degree burns from a smoldering mattress.

Poignant with touches of humor, “Miss D & Me” is a fitting fade-out for an actress who made it look easy to stay tough. Davis chose the epitaph for her tomb at Forest Lawn Hollywood: “She did it the hard way.” Yet Sermak’s book brings to mind a different Davis reflection that her fans will find more perceptive with each passing year: “Old age ain’t no place for sissies.”