The origins of ‘cool.’

From Slate: "Cool has come a long way, literally. In a 1973 essay called 'An Aesthetic of the Cool,' art historian Robert Farris Thompson traced the concept to the West African Yoruba idea of itutu — a quality of character denoting composure in the face of danger, as well as playfulness, humor, generosity and conciliation. It was carried to America with slavery and became a code through which to conceal rage and cope with brutality with dignity; it went on to inform the emotional textures of blues, jazz, the Harlem Renaissance … then percolated into the mainstream."