Perhaps as part of the subterfuge about her age, she often erased this chapter from her life story, preferring to identify with Oklahoma, where the family moved when she was 24, her mother died of flu and the grieving Mr. Skirvin built a grand eponymous hotel. Pearl briefly aspired to be an opera singer, which would deepen her relationship with Truman’s daughter, Margaret. For a while she chaperoned her sister, Marguerite, through a successful acting career.

Pearl met George Mesta, a 20-years-older Italian American steel magnate from Pittsburgh, during a dinner at the Waldorf Astoria Hotel in New York City. Their marriage lasted almost 10 years — “Oh, how I wanted children, but I just couldn’t,” she said — ending with his death of a heart attack and a pile of money for Pearl, soon to be (as it had sometimes been spelled on their travels to Europe) “Perle.”

With her siblings, she confronted her father’s shady accounting practices, and thanks to a female friend, she became an early advocate of the Equal Rights Amendment and blunt feminist instrument. For Mesta, life would indeed begin at 40, as a popular best seller of that era was titled. Most unusually for the subject of a biography, she’s approaching 70 well before the midpoint of this one, and you wonder how the following pages will ever be filled.

But then of course there is “Call Me Madam,” the 1950 Irving Berlin musical in which Ethel Merman starred as a thinly veiled version of Mesta, with a then-record $1 million in advance ticket sales and a lyric that would forever stick: “the hostess with the mostes’ on the ball.” (Watch the movie version for a quick infusion of daffy American midcentury optimism and the unexpectedly beautiful singing of the usually villainous George Sanders.) She was also said to be the inspiration for Dolly Harrison in Allen Drury’s 1959 novel “Advise and Consent.”

Extroversion was Mesta’s superpower, not introspection. “If you said intellectual integrity, I doubt if she’d know what you meant,” Cafritz sniffed. But her can-do could not be contained. On occasion she seems to exhaust even her biographer into mild syntactic blunder: “Anxious about her status, the sound of her ringing telephone was music to Perle’s ears” and the like.