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.
The cover image is from the Dover Pictorial Archive. The cover font is Adobe ITC Garamond. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont’s TheSansMonoCondensed.