It all began in 1919, when the University of Edinburgh presented the James Tait Black Prize to Hugh Walpole for his novel, Secret City and, in the biography category, to H. Festing Jones for his memoir of Samuel Butler.
The James Tait Black has the distinction of being Britain's oldest literary award and, with it, a trend was born. Over the years, book awards have proved wildly popular, with prizes for individual genres, first books, etc. You name it, there's a prize. Typically, recognition is given for the "best" book in a given category -- novel, biography, poetry, science fiction/fantasy, mystery, graphic novel, children's book, young adult -- which seems a tall-enough order to judge.