Jerry West aka Andrew Svenson (1910-1975)
American author born in New Jersey in 1910. Real name Andrew Svenson, though perhaps best known by the pen name of Jerry West, which he used to write his most popular and well-loved series: that of the 'Happy Hollisters.' This is a long running adventure series which has quite a cult following and it's own fan site. Some of the stories in the series are pony related, although the full series is actually a mystery/adventure series.
As well as the Hollisters series he also wrote other adventure series for children, including the Brett King and the Tolliver Family series. This latter series was written under another pseudonym (Alan Scott) and included one pony-related title.
The author in fact worked under a number of other pseudonyms with which he was to share with other authors as a staff writer (ghost writer) for the highly popular Stratmeyer Syndicate publishing company on such classic series as the Hardy Boys and Bobbsey Twins.
He advocated a 'formula' for writing exciting children's books in which the first page should plunge the reader into excitement and danger and that each chapter should end on a suspenseful note or 'cliff-hanger.'
The excellent fan site I have provided a link to gives a lot more information about the author and his works