Japanese American Mika is the newest member of the Lotus Lane Girls, with her very own new diary, but she is still troubled by tensions between her different friends, and worried about her project for the school newspaper.

Twelve-year-old Iveliz is trying to manage her mental health and advocate for the help and understanding she deserves, but in the meantime her new friend calls her crazy and her abuela Mimi dismisses the therapy and medicine Iveliz needs to feel like herself.

Nikki tries to be a pet sitter, but realizes it's harder work than she thought.

Eleven-year-old Harriet keeps notes on her classmates and neighbors in a secret notebook, but when some of the students read the notebook, they seek revenge.

Macy's little sister has wings that are too small, so Eva's class decides to raise money to buy her a flying chair, and half the class opens a bakery, and the other half opens a candy store--but soon competition between the two stores becomes more important than their goal, and Eva needs to convince the other owls that they will collect more money if everyone works as a team.

When she accidentally leaves her journal in Tiffany's apartment, Keena is afraid that Tiffany will reveal all of her secrets.

Eleven-year-old Tally is starting sixth grade at Kingswood Academy and she really wants to fit in, which means somehow hiding her autism, hypersensitivity to touch, and true self, and trying to act "normal" like her former best friend, Layla, who is distancing herself from Tally and her fourteen-year-old sister, Nell, who is always angry with Tally for being different; but as she records her thoughts and anxieties in her coping diary, Tally begins...

Spirited, restless Gracie Lockwood, twelve, of Cliffden, Maine, living in a world where sasquatches, dragons, giants, and mermaids are common, keeps a diary of her family's journey in a used Winnebago as they seek The Extraordinary World in hopes of keeping her little brother, Sam, safe against all odds.

Seventeen-year-old Margaret "Cuckoo" Clark keeps a journal detailing the trials and tribulations of high school life as she and her close-knit group of outcast friends try to break down the barriers between their school's "warring nations."

Originally published in Japanese: Tokyo : Shinchōsha, 1937. Told in two voices, fifteen-year-old Copper struggles to confront inevitable and enormous change after his father's death and his uncle writes to him in a journal, sharing knowledge and advice in 1937 Japan.