So, yes: Mr. Bennett is not a name that typically comes to mind when seeking advice about our current high-tech moment. But he should be.

In 1905, Mr. Bennett stepped away from his traditional genres to produce a short but remarkable volume of self-help literature titled “How to Live on 24 Hours a Day.” Targeted to the middle-class, white-collar workers who were filling in the growing London suburbs, Mr. Bennett argued that making the most of their leisure time was the key to cultivating a meaningful life. His suggestion for doing so was clear: rigorous intellectual self-improvement through reading and concentrated thought.

The specifics of this vision, in which the British “salaryman” scrutinizes Dante, are obviously dated. But there’s a deeper general truth lurking beneath the details: What you do with your spare time matters.

This idea, of course, is not new. In “The Nicomachean Ethics,” Aristotle argues that true human flourishing requires activities like philosophizing that are pursued for no other reason than their intrinsic quality. Seneca had similarly lofty visions for our time off, writing, “I am not sure that we cannot serve [the Commonwealth] better when we are at leisure to inquire into what virtue is.”

The wisdom of this timeless emphasis on quality leisure was made clear to me recently. Early last year, as part of the research process for my new book, “Digital Minimalism,” I asked for volunteers willing to spend January avoiding optional digital technologies in their personal life, including social media, online news, video games and streaming. Because this was a big sacrifice, I was expecting around a dozen brave souls to join me in this adventure. Instead, 1,600 people signed up.

Many of the participants in this digital declutter sent me reports about their experiences. One of the more striking findings was the degree to which low-quality, algorithmically optimized digital content had colonized their leisure time. When they powered down their devices, these declutterers were suddenly confronted with empty stretches that they had no idea how to fill.

Inspired by Mr. Bennett, I encouraged them to aggressively reintroduce high-value leisure activities that had nothing to do with glowing screens — even if these activities required more energy and commitment than clicking “next episode” or scrolling a Twitter feed. Many embraced my advice.

A graduate student named Unaiza replaced her habit of browsing Reddit at night with reading library books, finishing eight during her digital declutter.

“I could never have thought about doing that before,” she told me proudly.

Another volunteer, Melissa, revamped her social life, setting up dinners with friends and scheduling regular face-to-face time with her brother — who, to Melissa’s frustration, had a hard time looking up from his phone during their meetings. Yet another volunteer, Caleb, began journaling and listening to vinyl records from beginning to end. He told me the experience of listening to music is completely transformed when you lose the ability to tap “next” when you get antsy with the current song. An N.Y.U. student who wanted to stay informed during his declutter arranged to get a newspaper delivered to his dorm room, while a father named Tarald invested his reclaimed attention into remaining undistracted while with his children. He told me it felt “surreal” to be the only parent at the playground not looking down at an electronic device.

The positive effect of returning to these analog activities is so pronounced that I’ve come to think of this strategy like a magic pill of sorts for curing the low-grade anxiety and existential aimlessness that define our culture of constant connection. This effect seemed particularly powerful for young people who have never known life without an accompanying screen. Like sleep and exercise, this analog cure seems to have few downsides, and its benefits compound.

Administering this cure, however, isn’t an easy process.

Something that helps is recognizing the extent to which the digital stream has commandeered your attention. The articles that rank highly in your feeds were selected by algorithms that have studied your behavior and know with statistical certainty which headlines will keep you staring at your screen. Likes, photo tags, comments, favorites, retweets and other social approval indicators are engineered to make it nearly impossible to resist compulsively checking apps.

My advice to gain the upper hand in this struggle is to demobilize the digital stream. Remove from your phone any app that monetizes your time and attention, like Instagram, Twitter and Facebook. You don’t have to quit these services; you can still access them from a browser. But you’ve removed their ability to follow you throughout your day, persuasively manipulating your attention toward their own ends.

It’s also important to prepare yourself for the difficulty of reintroducing high-quality analog pursuits into your life. It’s easy to swap tweets with your digital tribe, but organizing an activity in your real-world community might require annoying logistics and force you to confront uncomfortable moments and social complexities.

But as Sherry Turkle poignantly asks, “Who said that you never have to have a moment of friction with difficult people or difficult moments, when did that become the good life?” Prepare yourself for this friction. It’s worth pushing through.

Early in his 1905 guide, Mr. Bennett labels our time “the most precious of possessions.” This is an observation worth remembering when great fortunes are being made by diverting this precious possession toward screens, where it can be alchemized into quarterly revenue numbers.

You can fight back. If you take whatever scraps of leisure your situation affords and commit them toward quality analog activity and away from dehumanizing digital consumption, you’ll take a strong stride away from simply existing and closer to actually living.

Cal Newport, a computer science professor at Georgetown, is the author of six books, including, most recently, “Digital Minimalism: Choosing a Focused Life in a Noisy World.”