Associated Press

Huguette in her last published photograph, in 1930, on the day of her divorce in Reno, Nevada. The heir to a copper fortune died in 2011 at 104.

A nonfiction book on the mysterious heiress Huguette Clark and her family is being written by an NBC News reporter and one of Clark's cousins.

Ballantine Bantam Dell, a division of Random House Publishing Group, has acquired "Empty Mansions," by Bill Dedman and Paul Clark Newell Jr.

Bill Dedman is a Pulitzer Prize-winning reporter for NBC News who introduced the public to heiress Huguette Clark and her empty mansions through his series of narratives on NBCNews.com and NBC's TODAY Show. He lives in suburban Connecticut, where he discovered the first of Clark's three vacant palaces. His narratives on the Clark family have been the most popular story in the history of NBCNews.com, topping 100 million page views. He received more than 1,000 letters and emails from readers of the Clark series, many of them confessing to an obsession with the mystery heiress. As a young woman in New York, actress Kimberly Belflower, explained to her Twitter followers: "Don't mind me, I'll just be reading about Huguette Clark for the rest of my life."

Paul Clark Newell Jr., a grandnephew of W.A. Clark, has researched the family history for 20 years, gathering a unique collection of Clark family photographs, letters and memoirs. He shared many conversations with Huguette Clark about her life and family, and accepted her invitation for a rare private tour of Bellosguardo, her $100 million oceanfront estate in Santa Barbara, Calif. A grandson of W.A. Clark's sister, Newell is Huguette Clark's cousin, not a descendant of her father, and he therefore is not a party to the legal action by relatives to inherit her fortune. He lives in the mountains of San Diego County, Calif.

Executive Editor Pamela Cannon made the deal for North American rights with agent Michael Carlisle of Inkwell Management.

Though she inherited one of the great mining fortunes of the 19th century, Huguette Marcelle Clark lived quietly into the 21st century, secluded under fake names in hospital rooms for more than two decades. Intensely shy, she was almost entirely alone. One of her attorneys represented her for 20 years without meeting her face to face, instead talking to her through a closed door.

Her father, William Andrews Clark, was one of the Copper Kings of Montana and a controversial U.S. senator, believed to be as wealthy as John D. Rockefeller in his day but largely forgotten since his death in 1925.

His youngest daughter, the reclusive heiress Huguette, became a well-known name again in the last year of her life, after her three empty mansions and sales of her personal property drew the attention of investigative reporter Dedman. Clark soon became a subject of public fascination, a trending topic of searches on Google and Yahoo, with fan pages on Facebook, though the last published photograph of her was made in 1930.

When she died in May 2011 at age 104, her obituary appeared on the front page of The New York Times. A legal battle has begun for her $400 million fortune, even as criminal investigations continue of the men who managed her money.

Previous stories in the Huguette Clark mystery series on NBCNews.com:

Archive of all stories, photos and videos

Photo narrative, "The Clarks: An American story of wealth, scandal and mystery," Feb. 26, 2010.

Printable version of the photo narrative, Feb. 26, 2010.

Clark family notes and sources, Feb. 26, 2010.

Investigative report, part one, "At 104, the mysterious heiress Huguette Clark is alone now: Relatives are kept away. Only her accountant and attorney visit. Who protects HuguetteClark, with 3 empty homes and no heirs?" Aug. 19, 2010.

Investigative report, part two, "Who is watching Huguette Clark's millions? Reclusive heiress's assets are sold by two advisers, one an accountant with a felony conviction. Another elderly client signed over his property to the same accountant and attorney," Aug. 20, 2010.

"Criminal probe begins into the finances of reclusive heiress Huguette Clark: Manhattan DA's Elder Abuse Unit is on the case. The same unit prosecuted the Brooke Astor case; Clark has about four times the wealth," Aug. 24, 2010.

"Report sparks welfare check on heiress Huguette Clark," Aug. 25, 2010.

"Generosity of an heiress: four homes for a nurse, gifts for attorney's family," Sept. 1, 2010.

"Huguette Clark, the reclusive heiress, has signed a will, attorney says," Sept. 2, 2010.

"Family of copper heiress asks court to protect her from attorney, accountant," Sept. 3, 2010.

"Attorney for 104-year-old heiress defends his handling of her finances," Sept. 7, 2010.

"Judge leaves pair under investigation in control of heiress Huguette Clark's fortune," Sept. 9, 2010.

"Huguette Clark, the reclusive copper heiress, dies at 104," May 24, 2011.

"Family excluded from Huguette Clark burial," May 26, 2011.

"Heiress Huguette Clark's will leaves $1 million to advisers," June 22, 2011.

"The 1 percent of the 1 percent: How Huguette Clark's millions were spent," Nov. 19, 2011.

"A $400 miillion twist: Huguette Clark signed two wills, one to her family," Nov. 28, 2011.

"Tax fraud alleged in estate of heiress Huguette Clark; accountant resigns," Dec. 21, 2011.

"Nurse, in line to inherit millions, battles family of heiress Huguette Clark," Dec. 22, 2011.

"Judge bounces attorney and accountant from estate of heiress Huguette Clark," Dec. 23, 2011.