Amy Schwartz, the author and illustrator of children’s books including What James Likes Best and Polka Dots for Poppy, has died, publisher Holiday House announced in a news release. Publishers Weekly reports that she was 68.

Schwartz, a San Diego native, was educated at Antioch College and the California College of Arts and Crafts. She worked at Simon & Schuster before making her debut as a children’s book writer-illustrator with Bea and Mrs. Jones in 1982.

Many more books followed, including Camper of the Week, A Teeny Tiny Baby, The Boys Team, and Dee Dee and Me. Her more recent books have included 100 Things I Know How To Do; a critic for Kirkus gave the book a starred review, writing, “Should you get this book? 100% yes.”

Schwartz is survived by her husband, Leonard S. Marcus, the author and children’s book historian, who said in a statement, “For all the time I knew her, she was caring and generous and funny and smart and such a canny observer of people, too.”

Schwartz’s admirers paid tribute to her on social media. On Twitter, writer and editor Lauren LeBlanc wrote, “Learning that the children's book author and illustrator Amy Schwartz passed away, I burst into tears. My youngest especially loved POLKA DOTS FOR POPPY, but Schwartz and I had become Instagram pals. This is such a shock; her gentle presence and kindness has been a balm.”

And journalist and novelist Kimberly Olson Fakih tweeted, “I was so sorry to hear of Amy Schwartz's passing on Sunday. Her ‘13 Stories About Harris’ and ‘13 Stories About Ayana’ are only her most recent of dozens of books that put a child's perspective first. My condolences to her family and all who knew her.”

Michael Schaub, a journalist and regular contributor to NPR, lives near Austin, Texas.