Australian philosopher Peter Singer's book Animal Liberation, published in 1975, exposed the realities of life for animals in factory farms and testing laboratories and provided a powerful moral basis for rethinking our relationship to them. Now, nearly 50 years on, Singer, 76, has a revised version titled Animal Liberation Now. It comes on the heels of an updated edition of his popular Ethics in the Real World, a collection of short essays dissecting important current events, first published in 2016. Singer, a utilitarian, is a professor of bioethics at Princeton University. In addition to his work on animal ethics, he is also regarded as the philosophical originator of a philanthropic social movement known as effective altruism, which argues for weighing up causes to achieve the most good.

Facial recognition technology is rapidly becoming ubiquitous, used in everything from security cameras to smartphones. But in the near future, humans may not be the only ones to be digitally captured. Researchers are training forms of artificial intelligence to recognize individual animals by their faces alone -- and even discern their emotional state just by reading their expressions. Much of the research into animal facial expressions has focused on species like dogs and horses. But some of the most cutting-edge work is aimed at an unlikely subject: the farmed hog.

You've probably heard of farm-to-table, or even farm-to-fork, agricultural movements that emphasize the connection between producers and consumers. Spread, a giant factory farm that grows lettuce in Kameoka, Kyoto Prefecture, is just one of more than 200 "plant factories" in Japan capable of harvesting 20,000 heads of lettuce every day. Their lettuce, which includes frilly and pleated varieties, is grown in a totally sterile environment: There's no soil or sunlight, no wind nor rain. The rich, dark-brown soil in which produce has traditionally been grown is utterly alien inside the factory. Instead, the lettuce is grown hydroponically, in a nutrient-rich gelatinous substance.