Julie Campbell (1908-1999)
Full name Julie Campbell Tatham. American author, mainly of children's novels. Born in Long Island, New York in 1908. As well as writing books, Ms. Campbell Tatham worked as an editor and ran her own literary agency.
Perhaps best known amongst book collectors as the creator of the long-running and very popular Trixie Belden mystery series. This was a Nancy Drew type series, although with a younger, more realistic and down-to-earth heroine. Although the series ran on into 39 titles Ms. Campbell Tatham only wrote the first six in the series, which was continued by other writers. The main character of Trixie loves horses and they feature in the books, although usually more as a backdrop than part of the main plot. I am not sure how much horse content was in the later books, I will be researching these at a later date.
The Trixie Belden brand name was later extended to cover a few other girl's stories in the 'Trixie Belden Presents' series of books by different authors. These included horse stories by Estelle Grey and the Shelley Peters series by Ellen Bosworth
Julie Campbell also wrote another mystery series featuring the character of Jinny Gordon, and wrote some of the Cherry Ames nursing stories. As far as I know these do not feature horses.
There is a comprehensive Trixie Belden website.