Barnum was an incredibly successful promoter and showman. He created and ran a travelling circus that was known as "The Greatest Show On Earth". He was aware of the public's obsession for the whacky, weird and outrageous and he exploited this by exaggerating and even making up his acts.
Preferring to use his brains rather than his hands to make his fortune, Barnum became extremely wealthy and was mainly known for his promotion and showmanship relating to his travelling circus. In 1880 he wrote a book called "The Art of Money Getting" which highlights how he made his fortune, became bankrupt and then worked his way back to the top again. Much of his guidance is still applicable today.