Pannonica Rothschild -- called Nica -- tried very hard to be an upstanding member of the famous banking family. She went to the right schools, married the right man -- a French baron, no less -- and had five children.

Ultimately, though, she couldn't do it. Seduced by jazz, she fled to New York and became patron to dozens of musicians, most famously Thelonious Monk.

Her fascinating life is the subject of "Nica's Dream," the second recent effort to tell this story; two years ago, Nica's grand-niece, Hannah Rothschild, produced a documentary, "The Jazz Baroness," which covered much of the same ground.

Both ascribe her willingness to give up a life of privilege to the difficulty of growing up a female Rothschild, of whom nothing more was expected than being a wife and mother.

The filmmaker does better describing what it was like growing up a Rothschild. Young Nica (1913-88) was not only offered a choice of breakfast milk, but also a choice of breed of cow from which it came. Dinner guests were offered fruit -- directly from miniature trees carried in by servants.

Author David Kastin, however, does a superior job in placing her in the context of the milieu. This was a time when no proper white woman -- let alone a wealthy baroness -- would openly associate with African-Americans, a time when jazz "was perceived as a serious threat not only to the prevailing social order, but to the integrity of Western culture itself," he writes.

Nica was a proto-feminist. She learned to fly when just 21 years old and, like her husband, was a medal-winning war hero during World War II. (She drove an ambulance.) Her husband joined the diplomatic service of the new French government, and they settled first in Oslo and then Mexico.

But after the excitement of wartime service, it was impossible to settle down. She made frequent trips to New York and on one, pianist Teddy Wilson insisted she listen to a recording of "'Round Midnight" by a newcomer, Monk.

"I had never heard anything remotely like it," she's quoted as saying. "I made him play it 20 times in a row. [It] affected me like nothing else I ever heard."

She extended her stay indefinitely and eventually moved there permanently, and became a benefactor to many. Her Rolls or Bentley became a familiar late-night sight outside jazz clubs. Pianist Hampton Hawes noted: "She'd give money to anyone who was broke, bring a bag of groceries to their families [and] help them get their cabaret cards."

Her home became a way station for musicians, who came to jam and get a meal. Charlie Parker died in her suite at the Stanhope Hotel, and Monk lived in her home in Weehawken, N.J.

But with one possible exception -- drummer Art Blakey -- her relationships were platonic. They were fed by a passion, but it was a passion for music.

Where Kastin excels is in re-creating the world of jazz in the '50s and '60s, as modernists moved from swing to bebop to improvisational music.

In a fitting coda, Nica asked her children to spread her ashes on the Hudson River "around midnight."

Curt Schleier is a book critic in New Jersey.