The author defines intelligence as a nimble, pleasure-linked capacity that extends and intensifies human understanding, and distinguishes it from the professional intelligentsia and from narrow specialized intellects. He critiques the tendency of writers and scholars to sacrifice versatility for vocation or public approval, and invokes a mythic shapeshifter to symbolize reality's continual flux that intelligence attempts to grasp. Subsequent sections examine ethical and aesthetic consequences, intellectual manners, and practical uses and abuses, while noting social and political forces that may foster or constrain the development of this adaptive faculty.