Kaoru Hayamine is a Japanese author and original creator known for his work in young adult mystery novels, many of which have been adapted into manga, anime, and live-action films. He was born on April 16, 1964, in Ise, Mie Prefecture, Japan. After graduating from the education department of Mie University with a degree in mathematics, he worked as an elementary school teacher. It was while searching for engaging books for his students that he began writing his own stories, a decision that led to his literary career.

Hayamine made his professional writing debut in 1989 when his novel Kaitō Piero won an honorable mention in the 30th Kodansha Children's Literature Newcomer Prize. He is the creator of several long-running novel series that form the core of his bibliography. Among the most prominent are the Meitantei Yumemizu Kiyoshirō no Jiken Note series, the Kaitō Queen series, and the Machi no Tom & Sawyer series.

Several of his original works have been adapted into other media, demonstrating his significance as a source material creator in the Japanese entertainment industry. The Kaitō Queen novel series has been adapted into anime. The theatrical anime Kaitō Queen wa Circus ga Osuki was released in 2022. This was followed by Mirage Queen vacances élégantes, an original video animation that premiered in the same year. The Machi no Tom & Sawyer novel series has also seen multiple adaptations. A manga adaptation, illustrated by Haruka Fukushima, was serialized in Kodansha's Shonen Magazine Edge from September 2015 to March 2017. Hayamine is credited as the original story creator for this manga. The popularity of the series further led to a live-action film and a television drama, both released in July 2021. Earlier in his career, his Meitantei Yumemizu Kiyoshirō series was adapted into an NHK educational drama titled Futago no Meitantei in 1999.

Hayamine's works are primarily in the mystery genre and are aimed at a young adult audience. A notable characteristic of his writing is a tendency to reuse characters and settings across different series, creating a shared universe where previous works are referenced and parodied. His ability to create compelling narratives for younger readers has established him as a respected figure in children's literature, with his works regularly adapted for film, television, and animation.