Horse & Pony Books:
FIRE IN THE WIND
(HOUGHTON MIFFLIN [USA] 1961)
ILLUSTRATED BY ROBERT MACLEAN
Reprinted in hardback by original publisher
SUMMARY: Historical horse/mystery story set against the backdrop of the real life events of the great Chicago fire of 1871. Jeff, son of a police detective, love horses but can't have any of his own. When a friend is accused of being responsible for a number of stolen horses in the area, Jeff sets out to prove his pal is innocent. In the midst of all this adventure, a fire breaks out in the city….
Not too hard to find in the USA and usually reasonably priced. Much harder to find elsewhere.