'The Secret Horse' by Marion Holland (1959 and 1988)

Original cover
'The Secret Horse," written and illustrated by Marion Holland, was dedicated to Marion's daughters, "they know why."
For reviews and copies for sale:
Amazon
Goodreads
LibraryThing
THE SECRET HORSE is represented by McINTOSH AND OTIS, Inc.
For reviews and copies for sale:
Amazon
Goodreads
LibraryThing
THE SECRET HORSE is represented by McINTOSH AND OTIS, Inc.