Horse & Pony Books:
(HENRY HOLT & CO [USA] 1941)
ILLUSTRATED BY ELEANOR ISELIN MASON
Reprinted in hardback
SUMMARY: Not to be confused with the High Hurdles series by Lauraine Snelling or the Ginny Elliot book!
Debby's life changes when she and her father have to move because of his new job and her horse Twinkle has to be sold. Everything however seems fine in their new life until her father's employee Mr. Scrimgoer comes home with his beautiful granddaughter, Claire….
Easy to find in America, harder elsewhere, but can be bought from the USA fairly cheaply.