Who is Larry Livingston from Reminiscences of a Stock Operator and what is their importance?

Larry Livingston is the main character of the book, fictionalized from the real-life stock speculator Jesse Livermore. His story starts as a young boy working in betting houses known as "bucket shops" in Boston. He has a knack for numbers and arithmetic and a very good memory, and is soon memorizing how various stocks behave and predicting their next actions. His ability to do this allows him to make a stake at a very young age, but he also gains a reputation for winning and is banned from speculating in Boston.