The animal on the cover of the Excel Scientific and Engineering Cookbook is a common genet (Genetta vulgaris or Genetta genetta), also known as a true or small-spotted genet. (The taxonomy of the genus is controversial, with several similar species and numerous proposed subspecies, reflecting many geographic and habitat-specific variations.) The animal's name is pronounced with a soft "g" and rhymes with "Senate," in contrast to the homographic surname of the French novelist and playwright of the theater of the absurd.

Related to but distinct from true cats, genets are members of the civet or viverrid family (Viverridae), which also includes the mongoose. The viverrids are generally regarded as the closest living descendants of the extinct common ancestor of the carnivores. The oldest genet fossils, found in Morocco, date back to the Pliocene. Genets were kept as pets by the ancient Egyptians and as rat catchers in Europe until they were eventually replaced by house cats (depictions of domesticated genets can be seen on European tapestries from the Middle Ages).

Common genets are distributed throughout southern Europe, parts of the Middle East, North Africa, and the savanna south of the Sahara. They prefer low altitudes but live in diverse habitats, including pine forests, olive groves, rocky areas, and scrublands. Genets are considered arboreal, but they also spend a large amount of time on the ground and are partial to streambanks. They are agile climbers, with semiretractable claws and an extremely flexible body that can squeeze through any opening large enough to admit the head. They are primarily solitary; genets of opposite sexes may share overlapping territory, but those of the same sex will not. They are mostly nocturnal, resting during the day in thickets and hollow trees. Genets do most of their hunting on the ground and, like cats, they hunt by stealth, crouching low to the ground and killing prey with a quick bite on the neck.

The genet is an opportunistic carnivore; its main prey are small mammals, but it rounds out its diet according to seasonal availability with birds, reptiles, amphibians, fish, insects, and fruits. Genets use their sense of smell for both hunting and communication; they convey social, mating, and territorial messages via secretions from several scent glands (although these are not as highly developed as those of civets, whose perineal glands have long played a role in the making of perfume and the unusual processing of Indonesian coffee beans called kopi luwak). Both sexes use flank and hind-leg rubbing to distribute olfactory cues, in addition to marking with perineal secretions (common among females) and urine (more popular with males).

Genets have five vocalizations: a hiccup (used primarily by mothers to call the litter, and by males during the mating period); a purr (used only during the first week of life); a mew (used by the young while still dependent); a growl (used by the young once their predatory behavior is fully developed); and a click (used by adults in aggressive interactions). In offensive stance, the dorsal fur bristles and the genet arches its back, opens its mouth, and bares its teeth.

The cover image is from Lydekker's Royal Natural History. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont's TheSans Mono Condensed.