Ricard Wyckoff -the Day Traders Bible(pdf)

Their chances were equal at the start of their pursuit as far as capital and opportunity. The profits were there, waiting to be won by either or both. The answer seems to be in the peculiar qualifications of the mind, highly potent in the successful trader, but not possessed by the other. There is, of course, an element of luck in every case, but pure luck could not be so sustained in Manning's case as to carry him through day trading operations covering a term of years.

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