Walter Farley is the one who introduced me to Thoroughbred Horse Racing.
In NC where I live, they don't have a track in the entire state (the only racing here is car racing) so I never knew of horse racing till I went see "The Black Stallion" when it came to movie theatres. I was enamored with the concept!
Once my elementary school librarian thought I was old enough, I read ALL the Walter Farley books I could get my hands on and that's how I found out about Man o'War! At first I thought he was fictional like "The Black" because I thought he was too good to be real.
Then I read "The Godolphin Arabian" and I thoguht Margarite Henry took the "character" of Man o'War for her book (mind you I was still in elementary school at the time, and the state outlawed all gambling, including horse racing so there was no one I could talk to about him).
It wasn't till much later, when I was a teenager, that I learned that this red wonder-horse was real and I've been hooked on him ever since.