The economic history since the 1980s is that of a stratospheric development of finance, yet few people from the general public really know what finance is, its objectives, its fields of action and its repercussions. Casino economy for billionaires at the expense of the people for some, divine structure of growth for others, what is sure is that finance does not leave indifferent! In the era of digital technology and crypto-currencies, anyone who improvises himself as a trader without knowing the basics of this sector exposes himself to unconsidered risks, both individual and collective.