E.L. Konigsburg, the author of “From the Mixed-up Files of Mrs. Basil E. Frankweiler” and other classics of children’s literature that have provided escape and companionship to generations of young readers, died April 19 at Inova Fairfax Hospital. She was 83.

Her death, of complications from a stroke, was confirmed by her son Paul Konigsburg. She was a longtime Florida resident and had lived for the past five years with another son in Ashburn.

Since her literary debut nearly half a century ago, Mrs. Konigsburg has been celebrated as one of the finest storytellers of her era and genre. Her books fill a shelf or more and reveal an uncommon understanding of young people — their hopes and fears, their longing for ad­ven­ture beyond bedroom walls and playground gates and their ability to overcome a common childhood affliction called loneliness.

Such was the reverence surrounding Mrs. Konigsburg that she twice received the Newbery Medal, one of the highest awards in children’s literature. She had the even rarer honor of being named a runner-up and winner in the same year, and for her first two published books.

In the late 1960s, then a Florida housewife with no agent, Mrs. Konigsburg mailed to the Atheneum publishing house in New York her first manuscript — a story of friendship and witchcraft that became “Jennifer, Hecate, Macbeth, William McKinley, and Me, Elizabeth.”

Newberry Medal-winning writer and artist E.L. Konigsburg in 2004. (Jon M. Fletcher/Associated Press)

While waiting for its publication, she began “From the Mixed-up Files,” the now-famous novel about sister-and-brother runaways who take up residence in New York City’s Metropolitan Museum of Art and untangle the mystery of a beguiling marble statue of an angel.

Both books were published in 1967, the first receiving the Newbery Honor and the second claiming the Newbery Medal. Three decades, more than a dozen books and millions of readers later, Mrs. Konigsburg received her second Newbery Medal for “The View from Saturday” (1996), about brainy academic quiz bowlers and their endeavors to find their way in the world.

As she told it, Mrs. Konigsburg had a special interest in middle-class children and their adolescence — “the problems,” she said, “that come about even though you don’t have to worry if you wear out your shoes.” She said she strove to write literature “that tackles the basic problems of who am I? What makes me the same as everyone else? What makes me different?”

Those were among the questions examined in the novel that remains her most noted, “From the Mixed-up Files of Mrs. Basil E. Frankweiler.” (The volume was turned into a 1973 movie, “The Hideways,” which featured Ingrid Bergman as the eponymous fictional art collector, and a 1995 television film with Lauren Bacall in the same part.)

The book follows the escapades of the precocious Claudia Kincaid and her brother Jamie, whom Claudia ropes into her conspiracy to steal away from their suburban home and become squatters at the Metropolitan Museum of Art. The venerable institution becomes their domain, with the kids sleeping in a centuries-old bed from the collection and bathing in a fountain.

Like many of Mrs. Konigsburg’s works, the book is a story of discovery and self-discovery. Mrs. Frankweiler notices something about Claudia that Mrs. Konigsburg had identified in her own children during a trip to Yellowstone National Park.

“Claudia doesn’t want ad­ven­ture,” says Mrs. Frankweiler. “She likes baths and feeling comfortable too much for that kind of thing. Secrets are the kind of adventure she needs. Secrets are safe, and they do much to make you different. On the inside, where it counts.”

Elaine Shirle Lobl was born Feb. 10, 1930, in New York City, and grew up in what she described as a small Pennsylvania town. Her parents, immigrants from Central Europe, ran a bar.

Many of her books were inspired by experiences in her own life. She was Jewish and, as a girl, felt “always an outsider, to a certain extent,” she told the Ledger of Lakeland, Fla. Her 1969 book “About the B’nai Bagels” followed a Little League team and one of its players, a young man about to be bar mitzvahed.

Mrs. Konigsburg received a bachelor’s degree in chemistry from what is now Carnegie Mellon University in 1952. (She began working toward a master’s degree in chemistry, her son said, but changed plans after two inadvertent explosions.) Her book “George” (1970) was about a chemistry student.

She pursued a lifelong interest in art. Besides the adventures she imagined at the Met, she wrote “The Second Mrs. Gioconda” (1975), about Leonardo da Vinci and his “Mona Lisa.”

After moving with her husband to Florida, Mrs. Konigsburg taught science at an all-girls school. There, she said, she gained insight into the inner world of children whose lives were not as easy as they might have seemed. The headmistress inspired the character of Mrs. Frankweiler.

Mrs. Konigsburg said she wrote “Jennifer, Hecate” after watching her daughter work to make new friends after a family move. Her children were her models for her cover art and illustrations, many of which Mrs. Konigsburg drew herself, and were her first audiences.

Her husband of 49 years, David Konigsburg, died in 2001. Survivors include two sons, Paul Konigsburg of Great Falls and Ross Konigsburg of Ashburn; her daughter, Laurie Konigsburg Todd of Nampa, Idaho; a sister; five grandchildren; and two great-grandchildren.

Mrs. Konigsburg was praised for the creativity of her titles. Her books included “A Proud Taste for Scarlet and Miniver” (1973), “Father’s Arcane Daughter” (1976), “The Dragon in the Ghetto Caper” (1974), “Journey to an 800 Number” (1982), “Up from Jericho Tel” (1986) and “T-Backs, T-Shirts, COAT, and Suit” (1993).

Her more recent books included “The Outcasts of 19 Schuyler Place” (2004), “The Mysterious Edge of the Heroic World” (2007) and “My Father’s Daughter” (2008).

Mrs. Konigsburg told an interviewer that she had plenty of “mixed-up files,” though she didn’t have as many as Mrs. Frankweiler. They included a folder on “Reviews that Fault Something for Not Being Something Else.”

The reviews from children were, perhaps, conclusive. Decades after “From the Mixed-up Files” was published, young visitors still bound through the entrance of the Metropolitan Museum of Art looking for an angel statue. Whether it is there or not is a discovery best left to them.