BARBARA VAN TUYL & PAT JOHNSON
American author. Wrote one pony series, the first two with co-author Pat Johnson. Also wrote quite a few non-fiction horse books.

Bonnie series:
Series about racehorse Bonnie (Sunbonnet) and her rider Julie.

1) SWEET RUNNING FILLY
(With Pat Johnson)
(SIGNET PB 1971)
SUMMARY: Julie rescues a neglected filly from a junk yard and becomes involved in a mystery when she finds out Bonnie is actually a stolen racehorse.

2) A HORSE CALLED BONNIE
(With Pat Johnson)
(SIGNET PB 1971)
SUMMARY: It seems like a dream come true for Julie to be racing her beloved Bonnie. But then things start to go wrong...

3) SUNBONNET: FILLY OF THE YEAR
(SIGNET PB 1973)
SUMMARY: More mystery and mayhem threatens Bonnie and Julie's racing career

4) BONNIE AND THE HAUNTED FARM
(SIGNET PB 1974)
SUMMARY: Julie now has 2 horses and another on the way! But strange happenings and ghostly goings on start to threaten her happiness.

5) THE BETRAYAL OF BONNIE
(SIGNET PB 1975)
SUMMARY: Julie is shocked when Bonnie tests positive for drugs. Who has been doping her favourite racehorse?

Collectors info:
Published in paperback only. Not published in the UK. Hard to find in the UK but fairly easy to get hold of in America.