The animal on the cover of DocBook 5: The Definitive Guide is a wood duck (Aix sponsa), also known as a Carolina duck. Often considered one of the most beautiful ducks in North America, the male wood duck has a metallic purple and green head with white streaks extending from its bill around the eyes and down to its blue and green, gold-flecked wings. It has a white neck, a chestnut-colored chest, a white or red bill, and yellow-orange legs and feet. Females have more brown, gray, and subdued hues.