The animal on the cover of Programming Pig is a domestic pig (Sus scrofa domesticus or Sus domesticus). While the larger pig family is naturally distributed in Africa, Asia, and Europe, domesticated pigs can now be found in nearly every part of the world that people inhabit. In fact, some pigs have been specifically bred to best equip them for various climates; for example, heavily coated varieties have been bred in colder climates. People have brought pigs with them almost wherever they go for good reason: in addition to their primary use as a source of food, humans have been using the skin, bones, and hair of pigs to make various tools and implements for millennia.

Domestic pigs are directly descended from wild boars, and evidence suggests that there have been three distinct domestication events; the first took place in the Tigris River Basin as early as 13,000 BC, the second in China, and the third in Europe, though the last likely occurred after Europeans were introduced to domestic pigs from the Middle East. Despite the long history, however, taxonomists do not agree as to the proper classification for the domestic pig. Some believe that domestic pigs remain simply a subspecies of the larger pig group including the wild boar (Sus scrofa), while others insist that they belong to a species all their own. In either case, there are several hundred breeds of domestic pig, each with its own particular characteristics.

Perhaps because of their long history and prominent role in human society, and their tendency toward social behavior, domestic pigs have appeared in film, literature, and other cultural media with regularity. Examples include “The Three Little Pigs,” Miss Piggy, and Porky the Pig. Additionally, domestic pigs have recently been recognized for their intelligence and their ability to be trained (similar to dogs), and have consequently begun to be treated as pets.

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.