This document discusses definitions and theories of intelligence. It defines intelligence as goal directed and adaptive behavior encompassing abilities like reasoning, problem solving, and learning. It describes several theories - Charles Spearman's theory of general intelligence "g", Louis Thurstone's theory of primary mental abilities including verbal comprehension and spatial visualization, and Robert Sternberg's triarchic theory comprising analytical, creative, and practical intelligence. It also discusses Daniel Goleman's emotional intelligence model involving self awareness, self management, social awareness, and relationship management.