But her private life — she married a drama coach, David LeGrant, in 1952, had a son in 1959 and lived in a house with a garden on Long Island — was not the suburban idyll portrayed by the entertainment media. The couple were divorced in 1965. In the late ’60s and early ’70s, Ms. Cook drank more and worked less. In 1973, her teenage son went to live with his father.
By then, as she acknowledged in an interview with The New York Times Magazine in 2005, she was virtually unemployable, an alcoholic mired in depression. She went on eating binges and grew to 250 pounds.
“I was not some lady drunk,” she said. “I was a real nonfunctioning alcoholic. Dishes, always in the sink. The kitchen a mess. The bathroom a mess. Everything a mess.”
It might have been the end of her career. But in 1974 she befriended the pianist and composer Wally Harper, and they began a 30-year collaboration that would restore her voice and re-establish her professional credentials, albeit in a new direction: in nightclubs, cabarets and concert halls.
They started at a theater-district supper club. Luciano Pavarotti’s manager heard them and arranged a Carnegie Hall concert in 1975. The performance was a sensation — and the beginning of a long road back. Soon they had a contract with CBS Records, for which they recorded songs from the musical theater and other American standards.
Ms. Cook stopped drinking in 1977, and the crippling effects of depression subsided. But she continued to struggle with obesity. She lost some weight, but realized she would never return to the svelte 106-pound figure of the 1950s and resolved to continue her comeback whatever her weight.
“I decided that I had to try to be comfortable with my body as it was, because otherwise you just live in a closet, you don’t go out,” she told The Times.
Over the next few years, she sang at cabarets in New York and London. Another Carnegie Hall concert in 1980 revealed that she had found a new, more mature identity as a singer. Paying less heed to the technical virtuosity that had thrilled audiences in big Broadway theaters, she now emphasized phrasing and styling to project a song’s emotions in smaller, more intimate settings.