Jan Berenstain, who wrote and illustrated the beloved, wildly popular Berenstain Bears children's books with her husband Stan, died Friday at age 88. (Stan Berenstain died in 2005.) When news broke Monday of Jan Berenstain's passing, her legion of followers waxed nostalgic about the duo's catalog of lesson-imparting books, in which a family of anthropomorphic bears offer guidance to young children on everything from dentist visits to the first day of school to the death of a loved one. Here, six little-known, surprising, and otherwise adorable facts about the cherished authors:

1. An astounding body of work
The Berenstains' catalog includes 300 books that have been translated into 23 different languages — most recently Icelandic and Arabic, points out Ashley Fetters at The A.V. Club. More than 260 million copies of the Berenstains' work have been printed.

2. Love at first sight
Stan and Jan met on their first day of art school in 1941. At age 18, they were each enrolled in the same first-year drawing class at the Philadelphia Museum of Industrial Art. They worked together writing and illustrating nearly every book in their catalog. According to their editor, Dave Linker, Stan supplied much of the humor, while Jan provided the "heart." In an interview with The Washington Post, Jan admitted that Mama "is based on me. But I'm not as nice or stalwart."

3. Surprising early careers
Before they were married in 1946, Stan served as a medical illustrator for an army hospital during World War II, and Jan worked as a riveter building Navy seaplanes and as a draftsman for the Army Corps of Engineers. After the war, their first collaboration was a cartoon series called "All in the Family" that ran in McCall's and Good Housekeeping for 35 years. "They found success with domestic humor, finding something laughable in burnt dinners and squabbles over who used up the toothpaste," says Elaine Woo at the Los Angeles Times.

4. A literary celebrity connection
Inspired by their two sons, Mike and Leo, the Berenstains decided to try their hands at penning a children's book. They took their idea straight to the top, contacting the editor-in-chief and president of Beginner Books, a division of Random House. That big shot took a liking to The Big Honey Hunt, a story about a family of human-like bears, and published the Berenstains' first book in 1962. The editor in question? None other than Theodor Geisel — better known as Dr. Seuss. Seuss even came up with the idea of naming the cartoon bears after the authors' family, adding the line "another adventure of the Berenstain Bears" to the cover of their second book, The Bike Lesson. "We never really would have thought of it," Jan said.

5. A close shave with penguins
The Berenstain Bears were nearly the Berenstain Penguins, according to The New York Times. But in the end, the authors decided that bears "were more like humans" because "they stand on two legs, their mothers are very good mothers, and so on." One of the few other species to make an appearance in the series? In 1994's New Neighbors, the Berenstain Bears confronted the subject of racism when an Asian-looking panda family moved in next door. 

6. Working until the end
After Stan passed away in 2005, Jan continued writing new books, often with the help of her son, Mike. The series has grown with the times, covering topics like the dangers of bringing guns to school, online safety, and childhood obesity. According to Mike, Jan had been working on two more books in her Pennsylvania home at the time of her death. "Every day she was very productive," he said. "[She] had been doing illustrations until the day before she passed away." In a 2011 interview, Jan told the Associated Press, "It's wonderful to do something you love for so many years. Not everyone has that."