The concept of "genius" has a long and somewhat intricate history. In ancient times, the heroes depicted in poems such as the Odyssey and the Aeneid performed great feats under the guidance of the gods; the writers of such poems themselves invoked the inspiration of divine forces in order to write incisively and powerfully. When the word "genius" entered into common English usage in the 14th century, it did so in a manner that recalled this tradition. In fact, "genius" referred to the guiding, perhaps divine spirit that determined the deeds of an astonishingly talented human, not to the talented person himself or herself.
As the Renaissance progressed, the idea of genius was transformed to indicate innate or natural capacity--and was to some extent removed from its original, religious meaning. The most revered Renaissance geniuses (e.g., Leonardo, Michelangelo, Shakespeare, and Milton) are remembered as men of great energy and versatility; today, their accomplishments are regarded as the finest expressions of human intellect and creativity, not necessarily as proof of exceptional divine favor. But genius has not always translated into immediate real-world success. Some of the now-recognized literary geniuses of the 19th century, for instance, spent much of their lives working in relative obscurity (for instance, Emily Dickinson) or toiling in poverty (for instance, Edgar Allan Poe).
Outliers mostly considers the theories of genius that have been in circulation for the past century. Yet Gladwell's book continues the long-lived inquiry into the relationship between genius-level abilities and how those abilities translate into real-world accomplishment. Of all the ideas about genius that Gladwell challenges, perhaps the one that he most vehemently rejects is the relationship between IQ and achievement. After all, Lewis Terman--an early 20th-century researcher who based much of his work on the idea that IQ translates into success--is referenced and strongly critiqued at multiple points in Outliers. Gladwell's own theory of genius posits that innate talent is not enough: conditions dictated by community, history, and opportunity must be favorable to allow such genius to manifest itself.