https://www.publishersweekly.com/pw/by-topic/childrens/childrens-industry-news/article/86740-obituary-patricia-reilly-giff.html

Excerpts:

Prolific children’s book author Patricia Reilly Giff, widely known for her Newbery Honor-winning novels Lily’s Crossing and Pictures of Hollis Woods, as well as humorous series including the Kids of the Polk Street School, died on June 22 at her home in Fairfield, Conn., following a long illness. She was 86...

....at age 40, that Giff first tried to write a book of her own. She said that her experience working with remedial students, who often faced difficult circumstances and had “unhappy faces,” was a big inspiration for her. “With my husband’s encouragement, I decided to say something to all these children. I began to write,” she told SATA. Giff also wanted to make her students laugh. Her husband spurred her on and even converted two adjacent closets in their apartment into a small writing studio where she could work. For several years she snatched time to write before school and “slowly and painfully,” Giff recounted, she crafted her first book, Today Was a Terrible Day, which was discovered in the slush pile and published by Viking in 1980.

Giff had found her writing voice, and clearly had much more to say to the students she was addressing in her books; she had published 10 books by 1984 when she stopped teaching and decided to write fulltime. That change coincided with another new chapter, when she and her husband moved to Weston, Conn.

For years she often produced multiple titles annually, creating the Kids of the Polk Street School series and two spin-off series, and a number of humorous novels. It wasn’t until the 1990s, when she had already written more than 60 books for young readers, that Giff embraced a shift in tone.. “The wonderful publisher Craig Virden [then publisher of Delacorte Press] said he believed I had a serious book in me,” Giff said in a q&a for Scholastic.com. “And so I began, tentatively at first, and soon loved writing seriously. Lily’s Crossing (Delacorte, 1997) was my first, which Craig ended up publishing!” Lily’s Crossing chronicles the experiences of a girl on vacation in the Rockaways during the summer of 1944 as her best friend moves away and her father goes to war overseas. Giff has said that she drew from personal memories for this story and that it took her four years to finish. The book received a 1998 Newbery Honor citation, the first of two that Giff would win. The second came in 2003 for Pictures of Hollis Woods (Random House/Wendy Lamb).

In all, Giff produced more than 100 books for young readers. But in addition to her writing, Giff combined her expertise and love of books to reach people in other ways, too. She served as educational consultant for Dell Yearling and Young Yearling Book and was an adviser and instructor to aspiring writers. In 1990, she and her husband and children opened a children’s bookstore in Fairfield, Conn., called The Dinosaur’s Paw, a name taken from the title of one of Giff’s Kids of the Polk Street School books....

https://groups.google.com/g/rec.arts.books.childrens/c/WHflz3S3E2s/m/edvg3ak3WPoJ
(birthday post from 2015 - it includes a link to her long booklist)

Excerpt:

....Giff explains, "I want the children to bubble up with laughter, or to
cry over my books. I want to picture them under a cherry tree or at the
library with my book in their hands. But more, I want to see them reading
in the classroom. I want to see children in solitude at their desks,
reading, absorbing, lost in a book."

Giff tries to write books "that say ordinary people are special." She
says, "All of my books are based in some way on my personal experiences,
or the experiences of members of my family, or the stories kids would tell
me in school." Therefore, when she runs out of ideas for her books, Giff
says, "I take a walk and look around. Maybe I spend some time in a
classroom and watch the kids for a while. Sometimes I lie on the living
room floor and remember my days in second grade or third. If all that
doesn't work, I ask Ali, or Jim, or Bill"--Giff's children, whose names
often appear in her books...