Nassim Nicholas Taleb (born 1960) (Arabic: نسيم نيقولا نجيب طالب‎) (alternative spellings of first name: Nessim or Nissim) is a literary essayist, epistemologist, scholar of randomness and knowledge, researcher, and former practitioner of mathematical finance[2][3][4][5]. As a pioneer of complex financial derivatives[6], he had as a "day job" a lengthy senior trading and financial mathematics career in New York City's Wall Street firms, before he started a second career as a scholar in the epistemology of chance events and focus on his project of mapping how to live and act in a world we do not understand, and how to come to grips with randomness and the unknown —which includes his black swan theory of unexpected rare events[7].