Thoroughbred is a series of young-adult novels that revolves around Kentucky Thoroughbred racing and equestrianism. The series was created in 1991 by Joanna Campbell (better known as Jo Ann Simon, previously Haessig), and comprises 72 main-line books, several "super editions" and a spin-off series, Ashleigh. The series focuses on a group of core characters across multiple decades. The books, which are intended for a primarily pre-teen, female audience, explore the characters' adventures in horse racing, eventing, and steeplechase. The books also explore the characters' familial and romantic relationships. Thoroughbred is published by HarperEntertainment, an imprint of HarperCollins. A total of twelve different authors have contributed to the series over the fifteen years of its existence. By book 15, there were two million Thoroughbred books in print. The series concluded in 2005. Source: Wikipedia (en)