Emotional intelligence (EI), emotional quotient (EQ) and emotional intelligence quotient (EIQ), is the capability of individuals to recognize their own emotions and those of others, discern between different feelings and label them appropriately, use emotional information to guide thinking and behavior, and adjust emotions to adapt to environments. Although the term first appeared in 1964, it gained popularity in the 1995 best-selling book "Emotional Intelligence", written by science journalist Daniel Goleman. Goleman defined EI as the array of skills and characteristics that drive leadership performance.