The US marks its 40 millionth Covid-19 case since the start of the pandemic, as delta continues to spread. / NBC News

Helen Branswell covers the debate over vaccine boosters, what to call them, and whether they're needed. / STAT

Advice for travelers reconsidering their trips in light of the delta variant. / NPR

German Lopez: As the coronavirus shifts from pandemic to endemic, what is our endgame? How many deaths a year will we tolerate? / Vox

See also: "Why You Might Not Be Returning to the Office Until Next Year." / The New York Times

Skeptics of careerism ask a simple question: "What if all that reasoning and endurance language is bullshit?" / Galaxy Brain

A valuable conversation with a parent whose kids are underconnected to the internet and rely on libraries for basic tech. / Slate

Nearly one in three Americans live in a county hit by a weather disaster in the past three months. / The Washington Post

In patriarchal China, "butler cafés" provide men who will listen attentively and not mansplain. / Sixth Tone

Interviews with women who've umpired men's finals at tennis Grand Slams. "A few years ago, that was inconceivable, but now it's happening." / The US Open

El Salvador becomes the first country to make bitcoin legal tender. / Gizmodo

A team of Danish scientists discover the world's northernmost island thanks to a GPS error. / VICE

See also: Brief tours of three very small apartments in New York City. / YouTube

An assessment of the reading material in a random Airbnb uncovers a love story. / A Saturday Letter

Jim Gavin explains why he left the TV world to start publishing books. / The Biblioracle Recommends

Ten of this fall's most anticipated books, according to Goodreads. / Fortune

A survey of "immersive art rooms"—enjoyable partly for the experience of being tricked. / Hyperallergic