Jennie Jerome was an American, and better yet a Brooklyn girl, born at what is now 197 Amity St. in Cobble Hill. As Charles Higham points out in “Dark Lady: Winston Churchill’s Mother and Her World” (Carroll & Graf, 256 pages, $25.95), a house at 426 Henry St. bears a large plaque that incorrectly proclaims it the place of her birth (and provides the wrong date for her birth, too). Her parents, as Mr. Higham notes, had lived there until shortly before she was born.

If Mr. Higham had maintained this level of careful accuracy throughout, his book might have supplanted Ralph G. Martin’s two-volume classic, “Jennie: The Life of Lady Randolph Churchill,” as the standard biography. But his flawed writing, poor construction, and factual errors leave Mr. Martin’s work undisturbed on its pedestal.

We remember Jennie Jerome for her famous son, born seven months into her marriage with the swashbuckling political adventurer, Lord Randolph Churchill. “She shone for me like the morning star,” Sir Winston wrote in “My Early Life.” “I loved her dearly — but at a distance.” Mr. Higham’s book suggests that a great many distinguished men loved her somewhat more closely. She was blessed with the kind of overwhelming classical beauty once found in cigar-box paintings, and many of her photographs confirm the judgment of an admirer who said she had something of the panther in her look.

She owed everything to her parents: much of her good looks to her mother, but her audacity and courage to her father, Leonard Jerome, for whom the Bronx’s Jerome Avenue and Jerome Park Reservoir are named. Like Bernard Baruch, he was less a businessman than a speculator — in nearly every market from Wall Street to real estate. Unlike Baruch, he lost several fortunes, and when the bill collectors became oppressive, the Jeromes would head for Europe until Leonard could put his affairs back in order.

Leonard Jerome ensured that his daughter had a superb education, something remarkable for a girl of the period: languages, music, history, jurisprudence, and politics. Behind her exotic beauty and warm, sensual nature was a keen, adventurous, and well-stocked intelligence. Part of Jennie’s relevance to our times lies in her candid use of every personal asset to advance her career and those of her first husband and sons.

These accomplishment may tempt us to overrate some aspects of her life. Thus, Mr. Higham makes much of her brief spate as publisher of the Anglo-Saxon Review, an extravagantly produced quarterly that folded after 10 issues. This should have been put in perspective. By 1901, when Lady Randolph’s magazine collapsed, the remarkable Mrs. Frank Leslie, who was smart and attractive herself, had been among America’s most successful magazine publishers for more than 30 years.

Mr. Higham is an extraordinarily prolific author, often on the bestseller lists, who specializes in gossipy biographies of celebrities and movie stars (he has also, much to his credit, published several books exploring the slimily profitable relations between major American businesses and the Third Reich). Yet “Dark Lady” is fatally flawed. The writing seems cramped and telegraphic, as if he had lost interest in his subject after completing his research. The story lacks the champagne effervescence of Lady Randolph’s gaudy career. Thus, Mr. Higham’s treatment of Jennie’s death is so ill-construed that we witness her funeral before realizing that she had died somewhere on the previous page.

The editing too is remarkably inept (Germany’s Iron Chancellor was Otto von Bismarck, not Otto Van Bismarck). And, despite the author’s proud assertion of original scholarship in numerous libraries, the book is rife with easily detected minor factual errors. The king of the Belgians during World War I was Albert, not Leopold. Anyone who had the time to read 200 books and more than 15,000 pages of documents during his research in archives from the Bronx to the Bodleian might have called the Belgian Embassy on that one. The gradual accumulation of such mistakes, combined with its poor execution, saps one’s confidence in the work.

Mr. Bryk last wrote for these pages on the Chicago Plan.