I'm a professional horse racing handicapper.
and I'm a degenerate gambler. what a coincidence. I do love that equestrian performance sport.
When was horse racing invented?
It's the most ancient of all sports . It has been around since time started and the sun started to rise in the sky. 
How much money is generated from gambling on horse racing?
More then you can imagine. In 2008 alone it generated over 115 billion. Yes billion. You must be rolling in the money with your handicapping skills. 
You know it. Are there different types of horse racing?
Yes, Horse races vary widely in format from country to country. 
Is betting on horses legal at all horse tracks?
occurred in Ancient Greece, Babylon, Syria, and Egypt. It also plays an important part of myth and legend, such as the contest between the steeds of the god Odin and the giant Hrungnir in Norse mythology.
Chariot racing was one of the most popular ancient Greek, Roman and Byzantine sports. Both chariot and mounted horse racing were events in the ancient Greek Olympics by 648 BC and were important in the other Panhellenic Games. It continued although chariot racing was often dangerous to both driver and horse, which frequently
Horse racing
Horse racing is an equestrian performance sport, typically involving two or more horses ridden by jockeys (or sometimes driven without riders) over a set distance for competition. It is one of the most ancient of all sports, as its basic premise – to identify which of two or more horses is the fastest over a set course or distance – has been unchanged since at least classical antiquity.
Horse races vary widely in format and many countries have developed their own particular traditions around the sport. Variations include restricting