The animals on the cover of Learning Web App Development are German Grey Heath (Graue Gehörnte Heidschnucke): long-haired, short-tailed sheep native to the northern hemisphere from Scotland to Siberia, and specifically in north Germany in a special area called the Luneburg Heath. Some breeds are classed as domestic species threatened with extinction, so their preservation is subsidized within the European Union.
The German Grey Heath’s hair is greyish and very long, but too coarse for most textile applications; the wool is suitable for only coarsely woven fabrics such as carpets. Both sexes have horns, which curl back on themselves, and their meat is said to have a gamey flavor, which makes it popular to consume.
Sheep numbers dropped off by the turn of the 20th century and have been in decline ever since. During the 1990s, however, many small farms throughout Germany started breeding the sheep and saved the German Grey Heath from extinction. In fact, these animals are so celebrated that “Moorland Sheep Day” takes place every year on the second Thursday in July in a small village in Germany. Young rams are presented to breeders and onlookers, and the best animals are awarded prizes.
The cover image is from Meyers Kleines Lexicon. The cover fonts are URW Typewriter and Guardian Sans. The text font is Adobe Minion Pro; the heading font is Adobe Myriad Condensed; and the code font is Dalton Maag’s Ubuntu Mono.