When Princess Daisy author Judith Krantz was writing her steamy million-selling 1970s and ‘80s blockbusters, one of her iron-clad rules was that at least one character had to lose their virginity.

Another was that nothing was to be held back.

“If you’re going to write a good erotic scene, you have to go into details,” Krantz, who died of natural causes on June 22 at her Bel Air home at the age of 91, told the Los Angeles Times in 1990.

“I don’t believe in thunder and lightning and fireworks exploding. I think people want to know what’s happening.”

Once called ‘the hardest-working woman in trash fiction’, Krantz was one of the world’s best-selling novelists, churning out 10,000 words a week in her soundproof writing room.

Krantz had a formula to drive her books to the top of best-seller lists.

“In my opinion, there are two things women will always be interested in – sex and shopping,” she said in 1994.

“The experience of reading a Judith Krantz novel is not unlike that of watching Lifestyles of the Rich and Famous while simultaneously flicking through glossy advertisements in Vogue,” Rita Felski wrote in the 2000 book Doing Time: Feminist Theory and Postmodern Culture.

Her novels “embody a sexual politics at once feminist and retrograde”, said The New York Times, noting Krantz’s powerful, sexually assertive career women heroines always had as their goal true love with “superlatively handsome, staggeringly virile and stupendously rich” men.

Krantz at a 1988 party in her honour with businessman Fred Hayman and author Jackie Collins. Photo: Getty

Her books had sold more than 85 million copies worldwide and been translated into 52 languages.

“She had this rare combination of commercial and creative,” her TV executive son Tony Krantz said.

Before turning to fiction at the age of 50 with first novel Scruples, Krantz wrote for magazines including McCall’s and Ladies Home Journal. As a contributing editor for Cosmopolitan in the 1970s, she rose to prominence with her story, ‘The Myth of the Multiple Orgasm’.

With the help of her husband, film and TV producer Steve Krantz, she turned her novels into a series of hit mini-series.

“My husband had urged me to try fiction for 15 years before I did,” she said in a 2001 profile on the website of Wellesley College, her 1948 alma mater.

“I believed that if I couldn’t write ‘literature,’ I shouldn’t write at all.

“Now, I would say to young women, do something you have a true feeling for, no matter how little talent you may believe you have.

“Let no masterwork be your goal – a modest goal may lead you further than you dream.”

Launching I’ll Take Manhattan with Donald Trump (left) at Trump Tower in 1986. Photo: Getty

Faithful readers loved what she did, and in 1980 Krantz signed a record-breaking $US3.2 million contract for the paperback rights to Princess Daisy.

But she wasn’t to everyone’s taste. Krantz’s giant deal was slammed by Roger W. Straus Jr, president of publishing house Farrar, Straus & Giroux, as “bad for publishers and bad for writers”.

English novelist Angela Carter once said Krantz’s books were like “being sealed inside a luxury shopping mall whilst being softly pelted with scented sex technique manuals.”

Krantz didn’t care.

“I write the best books I know how,” she said. “I can’t write any better than this.”

The eldest of three children raised in New York by a lawyer and advertising executive, Krantz worked in Paris as a fashion publicist after graduating from Wellesley.

Home in New York the next year, she started writing for Good Housekeeping, where she became fashion editor. At a Fourth of July party she met Steve Krantz and “fell in love with him the minute I saw him”.

Steve and Judith Krantz at their Los Angeles home in 1979. Photo: Getty

They married in 1953 and raised sons Tony and stockbroker Nick in the Bel Air home stuffed with Krantz’s favourite silver snuff boxes, 19th century glassware, her 40 Chanel suits and Hermès bags. Steve died in 2007.

Saying she had nothing more to write about, Krantz retired at the age of 70 after 10 novels.

“Imagination, she said, ‘was like champagne’,” the novelist Dora Levy Mossanen wrote in 2010 after dining with Krantz.

“Once one gets to the bottom of the bottle and the last dying bubble, it’s time to quit.”