Judith Krantz, who almost single-handedly turned the sex-and-shopping genre of fiction into the stuff of high commerce, making her one of the world’s best-selling novelists if not one of the most critically acclaimed, died on Saturday at her home in the Bel Air section of Los Angeles. She was 91.

Her publicist, John Tellem, confirmed the death.

Though she did not publish her first book until she was 50, Ms. Krantz reigned for decades afterward as the international queen of poolside reading. Her 10 novels — beginning with “Scruples” in 1978 and ending with “The Jewels of Tessa Kent” in 1998 — have together sold more than 85 million copies in more than 50 languages.

Most became television movies or mini-series, many of which were produced by Ms. Krantz’s husband, Steve Krantz.

What drove Ms. Krantz’s books to the tops of best seller lists time and again was a formula that she honed to glittering perfection: fevered horizontal activities combined with fevered vertical ones — the former taking place in sumptuously appointed bedrooms and five-star hotels, the latter anywhere with a cash register and astronomical price tags.