The cause was kidney failure, said his lawyer and agent, Conrad M. Rippy.
Mr. Falconer began his professional life in the 1980s as a protege of David Hockney, the British painter who established himself in Southern California and emerged as a seminal figure of pop and modern art. Mr. Falconer was in his late 30s when he tried his hand at picture books and made his literary debut in 2000 with the publication of a slim volume titled, simply, “Olivia.”
From the start, Olivia was a force to be reckoned with. The cover featured her name in towering block letters, with Mr. Falconer’s tucked inside on the title page in a comparatively retiring font. The opening words introduced the 6-year-old pig as being “good at lots of things,” chiefly “wearing people out.”
Olivia wore out an untold number of grown-ups over the years — but in a good way; “she even wears herself out,” the story notes — who read and reread the Olivia books to her legions of young fans. She was often described as a porcine heiress to the legacy of the equally precocious Eloise, the 1960s creation of author Kay Thompson and illustrator Hilary Knight.
“Unlike Eloise, Olivia doesn’t stride through the Plaza Hotel like a pint-size Patton,” New York Times book critic Dwight Garner wrote. “She lives instead with her family in a tidy Manhattan apartment. But Olivia resembles Eloise in both her fits of pique and her embryonic sense of chic. … She’s part Babe, part Liza Minnelli, hear her pipsqueak roar. Among her favorite things: high heels, Degas, accessories, Maria Callas.”
Rendered partly in charcoal in a style that Mr. Falconer said he aimed to be “clean and spare,” the first Olivia book received a Caldecott Honor, the runner-up to the Caldecott Medal for distinguished illustration in children’s literature.
Olivia’s escapades continued in titles including “Olivia Saves the Circus” (2001), “Olivia … and the Missing Toy” (2003), “Olivia Forms a Band” (2006), “Olivia Helps With Christmas” (2007), “Olivia Goes to Venice” (2010) and “Olivia and the Fairy Princesses” (2012).
She made her most recent appearance in “Olivia the Spy,” published in 2017. By that time, Olivia had been around for nearly two decades and was a literary and merchandising juggernaut.
Mr. Falconer’s success as a children’s author was an unexpected turn in his career. He had established himself as a painter in the 1980s, also working with Hockney, a noted stage designer, on set and costume designs of opera productions on both sides of the Atlantic.
Mr. Falconer later settled in New York City, where he was similarly engaged by the New York City Ballet. Beginning in 1996, he contributed more than 30 cover designs for the New Yorker magazine.
The Olivia stories began in the mid-1990s as a private project for Mr. Falconer’s niece, for whom the pig was named.
“The real Olivia is an extremely headstrong, imaginative child who, even at the age of three … could argue (or stonewall, or bulldoze, or filibuster) through any ‘inconvenience’ to achieve her goal,” Mr. Falconer later reflected. “Always in the nicest way, I might add; she’s very charming.”
He offered the Olivia character to a literary agency but was dismayed when agents argued that he should turn his drawings over to a professional author, who would pen a new story. But Mr. Falconer could not bear to give Olivia up.
Anne Schwartz, a children’s editor at Simon & Schuster who admired Mr. Falconer’s work for the New Yorker, later contacted him to gauge his interest in working as a book illustrator. When she saw the Olivia stories, she told USA Today, “I knew … I had something great, and it had landed in my lap.”
Like the real Olivia, the pig Olivia had two younger brothers, Ian and William. Last year, Mr. Falconer published the picture book “Two Dogs,” about a pair of Dachshunds, Augie and Perry, named after two other nephews.
Once, Mr. Falconer recounted, his niece Olivia accompanied him on a book-signing tour.
“There were 100 people in line,” he said. “So I’m rushing through my signature: Ian Falconer. Ian Falconer. Ian Falconer. And she’s slowly writing: O-L-I-V-I-A. She couldn’t be rushed.”
Ian Woodward Falconer was born in Ridgefield, Conn., on Aug. 25, 1959. His father was an architect. His mother renovated houses, co-owned a gourmet food store, taught art and operated a sailing school.
Mr. Falconer attended the Long Ridge School in Stamford, Conn., and Cambridge School of Weston in Massachusetts, both private institutions where he said he was allowed to pursue his early artistic interests.
He later studied art history at New York University before training in painting at the Parsons School of Design in Manhattan and the Otis College of Art and Design in Los Angeles.
Mr. Falconer met Hockney through Henry Geldzahler, an art critic and curator who was a mutual acquaintance. Mr. Falconer, who was two decades Hockney’s junior, was described as being his romantic partner for a period in addition to his artistic collaborator.
They worked together on productions at the Los Angeles Opera, the San Francisco Opera and the Royal Opera House in London’s Covent Garden area, among them Wagner’s “Tristan and Isolde,” Puccini’s “Turandot” and Richard Strauss’s “Die Frau ohne Schatten.” On the East Coast, Mr. Falconer did design for works including a production of Stravinsky’s “Scènes de Ballet” at the New York City Ballet.
Mr. Falconer’s survivors include his mother, Alexandra “Sandy” Falconer Austin of Rowayton, Conn., and two sisters.
Mr. Falconer’s early artistic and theatrical experience surfaced regularly in the Olivia books. In the first volume — which was blurbed by eminences including opera singer Joan Sutherland and ballet dancer Mikhail Baryshnikov — Olivia visits an art museum and gazes upon a painting of dancers by Degas, later imagining herself onstage.
She sees a work by Jackson Pollock, declares that she could make such a painting in “about five minutes” and, to her mother’s horror, “gives it a try” on the wall as soon as she gets home.
At the end of the day, she asks her mother to read “only five books.”
“No, Olivia, just one,” her mother replies.
“Oh, all right, three,” the mother agrees. “But that’s it!”
One of the volumes they select is a book about Callas, the opera diva.
“You know, you really wear me out,” the mother tells her when they finish. “But I love you anyway.”
To which Olivia replies, “I love you anyway too.”