Ai no Kusabi

is a Japanese novel written by Rieko Yoshihara. Originally serialized in the yaoi magazine Shousetsu June between December 1986 and October 1987, the story was collected into a hardbound novel that was released in Japan in 1990.

The novel was partially adapted into a two-episode original video animation by AIC with the first episode released in August 1992 and the second in May 1994. In November 1993, an audio drama entitled Erogenous Dark was released focusing on a time period left unexplored in the original novels. A new twelve-episode OVA adaptation, also from AIC, was scheduled to begin releasing in Japan in the spring of 2010, but was cancelled for financial reasons. The project was picked up again and was released on January 18, 2012. However, the series was once again discontinued after four episodes.

The novel is licensed for an English language release in North America by Digital Manga Publishing, which published the novel over an eight-volume series.

Plot
In a futuristic world where the Elites are assigned various social classes based on their hair color in the city of Tanagura. Iason Mink, a high-class "Blondie", runs into Riki, a black-haired "Mongrel", and makes him his "Pet", which Riki resents being. As Riki learns of the dangers Iason faces by keeping him, he finds himself developing feelings for his master. Focusing on the relationship between Iason and Riki, Ai no Kusabi also explores issues of caste systems and social exclusion.