Miya Kazuki is a Japanese light novelist and essayist, best known as the original creator of the Ascendance of a Bookworm franchise, which includes a light novel series, multiple manga adaptations, and an anime television series.

Kazuki began writing novels as a hobby during her second year of junior high school. After passing an entrance exam, she attended a national university. Following her graduation, she became busy with work and stopped writing. It was only after she got married and her child started kindergarten that she found free time to resume her passion for writing. In 2013, she started publishing her novel, originally titled Ascendance of a Bookworm: I'll Stop at Nothing to Become a Librarian, on the user-generated novel publishing website Shōsetsuka ni Narō. The story gained significant popularity online, which led to its official publication in print. In 2015, the series made its debut under the T.O. Books imprint with illustrations by You Shiina. From 2015 to 2017, she also wrote a series of essays for the magazine Minna no Toshokan, where she discussed various issues related to libraries.

The original light novel series, which concluded in 2023, spans 33 volumes and is divided into five parts that follow the journey of a book-loving protagonist reborn into a medieval European-style fantasy world. As the original creator, Kazuki has been actively involved in the adaptation of her work into other media. The first manga adaptation began serialization in 2015, with Kazuki credited as the story's author and overseeing the project to ensure the visual representation stayed true to the original narrative. She reviewed plot details, storyboards, and final versions, and contributed short stories and afterwords for the manga volumes. In 2019, Ascendance of a Bookworm was adapted into an anime series, where Kazuki played a pivotal role in production. Her responsibilities included script approval, reviewing character settings and visual elements, attending voice recording sessions, and actively collaborating with the director and voice actors to shape character portrayal and dialogue.

Kazuki has cited a wide range of influences on her writing, drawing from a lifetime of reading that includes girls' novels, overseas fantasy series like Harry Potter and The Lord of the Rings, and works by authors such as Natsuhiko Kyogoku. She has also conducted in-depth research into myths to build the world of her story. Her creative process is known to be meticulous, involving extensive world-building using over 50 reference books and plotting the entire story at multiple levels on paper before writing. Her husband serves as a first-level reader and editor, and she has recounted bouncing ideas off him, including a memorable instance where their conversation led to the creation of the iconic Glico Pose used in the anime's depiction of a religious ritual.

Miya Kazuki's work has achieved significant commercial and critical success. The Ascendance of a Bookworm light novel series has sold over 10 million copies in combined physical and digital sales. The series was ranked number one in the annual light novel guide book Kono Light Novel ga Sugoi! in the tankōbon category for 2018 and 2019, and again in 2023 before earning a place in the publication's Hall of Fame.