The title of this book is taken from an anecdote about Diogenes, the ancient Greek philosopher who was known for his self-imposed poverty and his cranky personality. While he was reading one day, outdoors in Corinth, he was approached by an admirer, Alexander the Great, who offered to grant him any wish. Diogenes only wanted to get back to what he was doing before the interruption. Rather than ask for a material benefit, he simply said: "Stand out of my light."

James Williams, a “former Google strategist, now Oxford-trained philosopher,” according to his author biography, applies the Diogenes story to our modern condition, one in which we are incessantly exposed to technologies that usurp our attention for the purposes of selling us things we don’t need or getting us to click links for websites that don’t improve our lives, or — what can be worse — that misinform us about public issues and that will in all cases distract us from making progress on whatever goals or projects we might have been pursuing before our attention was captured. Williams wants us first to recognize, then to push back against these interruptions for the sake of maintaining the integrity of our psyches, the bedrock of private experience as well as for the benefit of our communities and our society at large. This is a book of practical ethics, intended to effect changes in us, in the companies that control the technologies we live with, and in regulations that help shape those technologies.

People often say casually that we live in an information economy, where “content,” data, facts and news reports serve as commodities or currency. Williams, building on a concept advanced by the economist Herbert Simon, urges us to think instead in terms of an attention economy, where such information lures us to think about or otherwise engage with products and services whether they align with our previous desires and values or not. In this view, information uses up our resources of attention. And what is attention itself? Simon himself provides only a provisional definition: “whatever it is that information consumes.” This means that, again in Simon’s words, “a wealth of information creates a poverty of attention.”

To further nail down the meaning of the term, Williams briefly surveys the previous literature on attention, including comments by the seminal American psychologist and philosopher (and his near-namesake) William James. But he ultimately finds it more useful to shift the question from, “What is attention?” to “What do we pay when we ‘pay’ attention?” His answer: “You pay with all the things you could have attended to, but didn’t; all the goals you didn’t pursue, all the actions you didn’t take, and all the yous you could have been, had you attended to those other things.”

The book’s central chapters illuminate these unmet desires by examining three kinds of metaphoric light that interruptive technologies block from us: the spotlight of individual attention, the daylight in which we conduct our communal affairs and the starlight by which we orient ourselves with respect to enduring values.

The book ends with proposed “interventions." Its style lapses into jargon and cliché at times. Williams wants to reform the contemporary advertising industry, for example. We need a public conversation on the nature of advertising and a reinvigoration of advertising ethics, which is not a conspicuously robust discipline these days. He suggests that developers and designers could be required to take an oath, like the Hippocratic oath for doctors, that could lead them away from exploiting the more insidious methods of online persuasion. Like Woodrow Hartzog and other contemporary privacy advocates, he wants to elevate our expectations of corporate bodies so that, rather than behaving as the user’s adversary, they act as fiduciaries of our online experiences and the data-traces we leave.

Although privacy in the senses in which privacy professionals commonly think of it — regulatory frameworks, policy enforcement, and so forth — arises only intermittently, Williams’ book invites us to think in new ways about the most private of experiences, our moment-by-moment expenditure of attention. There is more to be said on the topic, of course, perhaps based on the inquiries William James began at the end of his career, in essays like “Does Consciousness Exist?” (1904). But that’s another book.

This one will do for now, if you wish to expand your sense of why privacy matters.