Introducing “How the System Works,” a series on the hidden mechanisms that support modern life. As Mann points out, “No poets celebrate the sewage treatment plants that prevent them from dying of dysentery.” Lots of illuminating insights in the first essay, for example:

Today more than 1 percent of the world’s industrial energy is devoted to making ammonia fertilizer. “That 1 percent,” the futurist Ramez Naam says, “roughly doubles the amount of food the world can grow.”