“I was never really a marcher,” says Naomi Klein, an author so politically committed that she discovered she was pregnant with her son, Toma, while among Occupy Wall Street protesters in Zuccotti Park. “Even though I believe in mass social movements, I’m uncomfortable in crowds.”

On this sultry summer evening, we’re sitting in a place where the attractive 44-year-old Toronto resident does feel comfortable. We’ve convened at Soos Resto/Bar, a newfangled Malaysian café, for dinner with a group of friends including her lanky, droll Random House editor, Louise Dennys (the niece of Graham Greene), avant-garde filmmaker John Greyson, fiction writer Kyo Maclear and her composer husband, David Wall, a onetime member of the almost-famous alt-rock band Bourbon Tabernacle Choir. As the wine and conversation flow, we all devour plates of nasi lemak ordered by Klein’s husband, Avi Lewis, a TV host and documentary filmmaker who exudes graciousness and transparently adores his wife. “On our honeymoon,” Klein tells me, laughing, “I made him visit Nike sweatshops!”

She’s in high spirits, and why not? A few days earlier she finished writing This Changes Everything, which she calls “a book about climate change for people who don’t read books about climate change.” She can now enjoy a few weeks of calm before the media onslaught (and inevitable controversy) when it’s published simultaneously by four publishers in four different countries on September 16. That’s one week before the United Nations’ 2014 Climate Summit, an event certain to bring throngs of demonstrators to the streets of Manhattan—including Klein, who sits on the board of 350.org, a grassroots group devoted to creating a global climate movement. “New York is going to be on fire when this book comes out,” she says, speaking (one hopes) metaphorically.

Like all of Klein’s writing, This Changes Everything challenges the values by which we live. Her earlier books, No Logo (2000) and The Shock Doctrine (2007)—she’s got a knack for catchy titles—weren’t merely worldwide best sellers but cultural lightning bolts that suddenly illuminated for readers what had been happening around them. While the former became the bible of the antiglobalization movement, the latter was a groundbreaking study of how neoliberal free marketeers have seized on moments of social crisis—whether in the post-coup Chile of 1973, post-Communist Russia in the nineties, or postwar Iraq after the toppling of Saddam—to impose a kind of shock therapy, transferring public resources into the hands of the wealthy and demanding austerity of ordinary citizens. It anticipated how the 2008 financial crisis would lead to policies that served Wall Street while leaving Main Street to fend for itself. Small wonder it received glowing reviews from the likes of Nobel Prize–winning economist Joseph Stiglitz and John Gray, a professor of political philosophy at London School of Economics who wrote in The Guardian, “There are very few books that really help us understand the present. The Shock Doctrine is one of those books.”