“Flowers in the Attic” — the 1979 bestseller — continues to shock and thrill readers more than 40 years later. The gothic horror classic about four siblings who spend three years locked in the attic of their grandparents’ mansion while their mother tries to win back her inheritance, contains just about every kind of taboo: murder, religious fanaticism, child abuse, rape, incest. 

It’s so outlandish, fans have long wondered if author “VC Andrews” based the novel — and its various sequels — on her own life. In her public appearances, Andrews herself seemed like a fairytale figure: a platinum blonde beauty bound to a wheelchair, her watchful mother permanently at her side. 

While the new book “The Woman Beyond the Attic: The V.C. Andrews Story” (Gallery Books) by Andrew Neiderman may not be as salacious as “Flowers in the Attic,” it’s surely worth its own Lifetime Original Movie. Neiderman — who has continued pumping out VC Andrews novels since her death in 1986 — had access to Andrews’ letters and manuscripts and interviewed dozens of family members to get the inside scoop on the author. 

Cleo “Virginia” Andrews was born 1923 in Portsmouth, Va., the second of three children born to World War I vet William and telephone operator Lillian Andrews — and their only girl. Her two parents spoiled little “Virginia,” always buying her “beautiful things,” her cousin Pat told Neiderman. “When rubber bathing suits were the rage, Virginia had one in every color. Forty-dollar blankets were casually purchased when 40 dollars was a fortune.”

The young family struggled to survive on William’s income from the US Navy, and — before Virginia’s youngest brother came along — they lived in Lillian’s parents’ four-bedroom house, along with Lillian’s five siblings. 

Andrews had an active imagination. She loved fairy tales and gothic romances like “Jane Eyre” and “Dracula,” which scared her so much that she would put a piece of garlic at her bedroom window to ward off the vampire. She channeled her creativity into drawing and painting: Her second-grade teacher, so impressed with her skills, sent 7-year-old Virginia to junior college for art lessons, where she had to sit on top of a dictionary to see the front of the room. 

As an adult, Andrews loved telling the story about how Frank Lloyd Wright came to her class and asked her about a sketch she did. 

“Why did you draw a round house with all glass?” he asked. 

“Well, it’s my mother,” 7-year-old Virginia said. “She always complains that she never seems to have enough windows.”

According to Andrews, Wright looked at her teacher and said, “A child like that scares the hell out of me.”

Andrews had beauty, brains, talent and imagination, but something happened at 17 that would alter the course of her life. 

She tripped on a stairway at school, badly twisting her hip. The stumble seemed to cause a bone spur that threw her spine out of alignment, exacerbating an arthritic condition that was already there. She went through two surgeries and was put in a full-body cast, which only made things worse. 

Andrews was told she would spend the rest of her life on crutches and in wheelchairs. She never went back to school, and became completely dependent on her parents. 

Her mother, in particular, could not hide her shame.

“Let’s not allow anyone to see my ‘afflicted daughter,’” she would say when positioning Virginia behind two conifer trees on the front yard, so she could sit on the front porch shielded from their neighbors.

When asked how she could bear being shut in, Andrews would respond: “I imagine I am a princess in a castle enjoying life.” Her parents still bought her pretty chiffon dresses and jewelry, and she would dress up, paint her face and coif her hair, despite having nowhere to go. One cousin remarked that she seemed like a “romantic princess” in the style of Rapunzel.

William died in the 1950s, when Virginia was in her 30s. William’s pension checks were meager, as were Virginia’s disability payments, so Virginia began selling her artwork — sumptuous velvet paintings of flowers that her mother would carry to the local department store and hawk herself. 

If Virginia led a hermetic life before, her life became particularly lonely after William’s death. Lillian hid her daughter away more than ever: She shopped for her, monitored her visitors and rarely let her out of the house. 

“She hungered for fun and excitement,” said her cousin Pat, recalling how she would take Virginia out to bars and restaurants despite Lillian’s protests when the two stayed with her in Atlanta. When Pat took her to Lord & Taylor, Andrews admitted she hadn’t been to a shoe store since she was 16. She was 41. 

At some point, Virginia stopped doing art and began writing stories, salacious tales that she said she published under a pseudonym. (One sample title of an early unpublished manuscript: “I Slept With My Uncle on My Wedding Night.”)

Neiderman doesn’t explain how Andrews got the itch to write about incest, but the general idea for “Flowers in the Attic” was inspired by a true story. When Virginia was undergoing surgery for her spine troubles at 17, she became close to one of her doctors. One day, he told her a shocking story: that he and his siblings had spent six years hidden away in a family mansion to preserve an inheritance. 

The tale stuck with her for decades.

Andrews claimed that she wrote “Flowers in the Attic” in two weeks, combining the doctor’s tale with a dash of fairy tale horror and some of her own experiences (the fire-and-brimstone church her grandfather made them attend in Portsmouth, her own entrapment). A virgin, she consulted medical books and her teenage niece to help give the sex scenes their technical and emotional veracity. 

“I lost 12 pounds [in the weeks writing it] it upset me so much, for I lived through everything those children suffered,” Andrews said. If her earlier stories were warm-ups, “Flowers in the Attic” represented her true potential, her masterpiece, and she was very proud of it. This work she published under her own name.

Immediately upon its 1979 debut, the book was banned in libraries and bookstores across the country, dismissed as “deranged swill” by one review. But the book, which was published by Pocket Books, a division of Simon & Schuster, became an instant bestseller. Suddenly, Andrews had a limo with her own chauffeur and was traveling the country for book signings and interviews. Readers wrote letters to her, begging for sequels. She was a famous author at the age of 57.

Andrews dedicated “Flowers” to her mother, but Lillian — hearing that the book featured incest — refused to read it, or any of the other novels her daughter would write. Still, she remained a steadfast presence at her daughter’s public events, accompanying her on book tours to France and England, and sitting beside her during all her signings. Andrews bought a house for the two of them in Virginia Beach in 1980, and their codependence made some fans wonder if the fraught relationship between Cathy, the dreamy teen protagonist of “Flowers,” and her scheming mother was based in some truth.

Andrews relished her new life, going to Hollywood in 1983 and even making a cameo in the film version of “Flowers in the Attic.” She churned out six more novels, flirted with men (though her mother’s constant presence made any real relationship impossible) and tried to make up for those 40 years she spent shut away from the world. She died in 1986, of breast cancer — seven years prior to Lillian, who passed away in 1993 in Naples, Fla., where her sons had set her up in a house with a caretaker.

At the time of Andrews’ death, she was working on her fourth “Flowers” book — a prequel — and her publisher asked Neiderman if he could finish it, and keep writing novels under her name. Now 81, he’s written some 60 of them, and doesn’t seem to be slowing down. This year will bring two more VC Andrews books, along with the biography, and last year Lifetime premiered four movies based on her works.

Andrews foresaw it all.

“All my life I thought I was meant to be something special,” she once said. “I never knew what it was. Now I have the satisfaction of having my name recognized. And it will live after me.”