Jan Berenstain, the children’s author who with her husband created the Berenstain Bears, whose winsome antics filled more than 300 picture books and helped guide millions of young readers through the vicissitudes of childhood, died Feb. 24 at a hospital near her home in Bucks County, Pa. She was 88.

She had suffered a stroke last week, her son Michael Berenstain said. Her husband, Stan Berenstain, died in 2005 at 82.

Few American youngsters finish elementary school without taking a walk “down a sunny dirt road deep in Bear Country” and getting to know Mrs. Berenstain’s treehouse-dwelling ursine family — hapless Papa in his overalls, wise Mama in her polka-dot dress and kerchief, and their three archetypal children.

Since the release in 1962 of the first Berenstain Bears volume, “The Big Honey Hunt,” the series has sold about 260 million books. Those books have been translated into almost two dozen languages and have inspired television shows, amusement park rides, McDonald’s Happy Meal collectibles and animal crackers made in the bears’ images.

Over the years, the Berenstains drew criticism for promoting long-outmoded gender roles and overly simple life lessons. But readers who love Bear Country consider it a place not unlike Mr. Rogers’s neighborhood, where a fixed storytelling routine and familiar characters bring comfort to children as they seek to navigate a world that becomes ever more complicated as they grow up.

In their books, Mrs. Berenstain and her husband seldom allowed the bear cubs to face more than one hurdle or affliction at a time. Over the years, they encountered a new baby, the first day of school, a trip to the dentist, bullies, stage fright, fear of the dark and jealousy — just a few episodes in the history of the Berenstain Bears family.

The books reinforced the sorts of lessons most parents try to impart on their children: Dentists aren’t as scary as they may seem, bullies aren’t as strong as they look, stage fright can be surmounted.

Bear Country morality was based largely on the Golden Rule rather than on religion. (Mrs. Berenstain was Episcopalian; her husband was Jewish.) Young readers closed Berenstain Bears books having learned that life is better when you are nice to others, and also when you keep a tidy bedroom.

Much of the wisdom contained in the Berenstain Bears books come from Mama Bear. Her relationship with Papa Bear, a sort of blundering foil, was occasionally attacked by critics. In a 1989 column in The Washington Post, columnist Charles Krauthammer called Papa Bear “the Alan Alda of Grizzlies, a wimp so passive and fumbling he makes Dagwood Bumstead look like Batman.”

The Berenstains often said that the Berenstain Bears parents were based on themselves. When Stan Berenstain died, Mrs. Berenstain told the New York Times that her husband had no qualms about Papa Bear.

“Nobody likes making a mother the fall guy,” she said. “Papa Bear has broad shoulders.”

Janice Marian Grant was born July 26, 1923, in Philadelphia, where she met Stanley Berenstain on the first day of art school. During their classes, they often went to the zoo and drew — among other animals — bears.

During World War II, Stanley worked stateside as a military medical artist; Janice did drafting work for the Army Corps of Engineers and worked as a riveter on Navy seaplanes. She made their wedding rings from airplane aluminum, and the couple was married in 1946. One of their first purchases for their new home was a drawing table.

From the beginning of their marriage, their working relationship was deeply collaborative. In the post-war years, the Berenstains became successful and prolific cartoonists. Their work regularly appeared in magazines including the Saturday Evening Post and Collier’s. They began a cartoon series, “All in the Family,” that ran for more than three decades in magazines such as McCall’s and Good Housekeeping.

In that series, as with the Berenstain Bears, they took turns writing and illustrating. (Years later, Mrs. Berenstain would complain about the tedium of drawing the “billions” of polka-dots on Mama Bear’s dresses.) The innocent humor of the Berenstain Bears is found in other books from the early years of their career, including “How to Teach Your Children About Sex Without Making a Complete Fool of Yourself” and “Have a Baby, My Wife Just Had a Cigar!”

The creation of the bears series came in part thanks to the Berenstains’ children, who were early fans of Theodor Geisel — better known as Dr. Seuss, the author of “The Cat in the Hat.”

The Berenstains decided that they, too, would try their hand at a children’s book based on an animal, and submitted “Freddy Bear’s Spanking” to the Random House publishing company. (The chose to write about bears not because their last name offered a convenient alliteration, but because bears were easy to draw.)

Geisel, then a children’s editor at the publishing house, liked the concept. He edited 17 books in the Berenstain Bears series, including the first published one, “The Big Honey Hunt.” He also shortened the Berenstains’ names to Stan and Jan for a rhyme on the cover.

Royalty papers mistakenly referred to their first book as “The Big Money Hunt,” the New York Times once reported. Nearly everyone, including the Berenstains, was pleasantly surprised by the book’s quick success. The television shows and other spinoffs only deepened the series’ cultural penetration. (Once, CBS refused to air a television episode based on the book “The Berenstain Bears and Too Much TV”; PBS later produced it.)

Survivors include two sons, Michael Berenstain, an illustrator and writer, and Leo Berenstain, a businessman, both of Bucks County and both of whom have worked on the family’s multimillion-dollar corporation Berenstain Enterprises; and four grandchildren.

Over the years, detractors took aim at the bears’ almost impossible wholesomeness, their attire that never changed with the times, and the tepid games the children played (they included hopscotch and jacks).

A Random House editor once told the Berenstains that “it’s just not that way in the real world,” The Post reported.

“But it’s that way in Bear Country,” the Berenstains said.