A hand’s primary function, Elias Canetti writes in Crowds and Power, is as “a claw to grasp whole branches” while climbing; both hands partner in “grasping” and “letting go.” This is like trade, he argues: “one hand tenaciously holds on to the object with which it seeks to tempt the stranger” while the other “is stretched out in demand.” Trading, then, offers “profound and universal pleasure” as “a translation into nonphysical terms of one of the oldest movement patterns.”

Before leaving his post as Qi chancellor in 193 bc, Cao Can gave advice to his successor: “If you stir up the markets and empty out the jails, then evil men will have no place to stay and will make trouble for you elsewhere.” A footnote in the English text from translator Burton Watson explains: “It was an assumption among Han officials and intellectuals that most, if not all, men engaged in trade were swindlers.”

The head female of a paper-wasp nest allows others to occupy space in her home—so long as they help raise her offspring. The labor market is, however, elastic: if other nests nearby have childcare needs, she maintains a lower work requirement from her “helper” wasps.

Including trademarks in books became crucial after the invention of the printing press; without stringent copyright laws, rival publishers could repurpose superiorly edited texts with impunity. Aldus Manutius of Venice, who employed Erasmus as a proofreader, called attention to his company’s “sign of the dolphin wound round the anchor.” Florentine printers were aping the mark, but in the frauds, “the head of the dolphin is turned to the left, whereas that of ours is well known to be turned to the right.”

A growing market for ejiao—a gelatin made from donkey hide believed by practitioners of traditional Chinese medicine to increase libido and slow aging—has led to a global trade of millions of donkey skins each year. Asses are often kidnapped from rural African villages, where their labor is valued highly, then taken to markets and slaughtered for export. “The donkeys,” said a sanctuary manager while visiting a market in Tanzania, “are very stressed.”