Jane Munro Gaymer (b.1933) is an author about whom alas I know nothing, so as usual if anyone can supply any biographical information I would be very grateful. From her date of birth, which is given in the Library of Congress Catalog but not in the British Library, it looks as if her books were written while she was very young. Her first, I Found Happiness, is I think non-fiction on how to manage your horse. Brownie is set on Exmoor, and is the story of an Exmoor pony. The illustrations are delightful and really quite staggeringly good for someone of 17, if indeed the Library of Congress has her birthdate right.
Finding the books
Both are reasonably easy to find, but much less so with their dustjackets.
Sources and links
British Library and National Library of Congress Catalogues
Many thanks to Sarah Beasley for the picture of the dustjacket for Brownie.
Bibliography: pony books only
I Found Happiness: the Happiness of Horse and Rider, Hollis & Carter, London, 1949, 171 pp.
Brownie, Hollis & Carter, London, 1950, illus the author.