Isabel McLennan McMeekin (1895-1973)

American author and playwright. She seems to have been a quite prolific and fairly eclectic writer, penning fiction and non-fiction, adult and children's books, biographies, poetry and plays! She also collaborated with Dorothy Park Clark on a number of novels, their joint psuedonym being Clark McMeekin.

I am not sure what her connection was with horses, but she must have known something about them, having written a non-fiction children's guide to horses, as well as some pony stories. Her best known pony book is the fictionalised account of the small chestnut racehorse Aristides who won the first ever Kentucky Derby.

Horse & Pony Books:

KENTUCKY DERBY WINNER
(McKAY [USA] 1949)
ILLUSTRATED BY CORINNE BOYD DILLON
Reprinted in hardback a number of times by original publisher
Reprinted in hardback by Grosset & Dunlap as part of their Famous Horse Stories series.
SUMMARY: Fictionalised account of Aristides, winner of the first ever Kentucky Derby.

BAN-JOE AND GREY EAGLE
(FRANKLIN WATS [USA] 1951)
ILLUSTRATED BY CORINNE BOYD DILLON
SUMMARY: Orphan Ban-Joe works in a racing stable and dreams of becoming a jockey and riding the big grey horse Grey Eagle.

THE POSTMAN'S PONY
(PUTNAM'S SONS [USA] 1960)
ILLUSTRATED BY CHET KALM

Collector's Info:
The Postman's Pony is quite rare, the other two are easy to find in the USA. All however are hard to find elsewhere.