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’ 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 allow 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.

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.

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.”

From the beginning of their marriage, their working relationship was deeply collaborative. In the postwar 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.

The creation of the bears series came thanks in part to the Berenstains’ children, who were early fans of 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 Random House.