October 17, 2014 7:30 AM EDT

More than a billion people live on a dollar a day, but their lives can seem worlds apart for the more fortunate among us. In a new work of photojournalism, poverty activist Thomas A. Nazario and Pulitzer Prize-winning photographer Renée Byer document the lives of the world’s most impoverished in a series of profiles, charts and photographs.

In ten chapters, Living on a Dollar a Day moves across four continents each with a focus on different issues facing those living in extreme poverty. One chapter focuses on subsistence living, another on slums. We get a bit of a respite in the chapters “And Yet the Children Play” and “Hope.” It’s at times a sad experience, though moving nonetheless.

The book also serves as a call to action. Each chapter ends with information about how readers can get involved in the fight on poverty.

“I was humbled by the grace, generosity, fortitude and bravery of the hardworking men, women, and children who allowed me into their lives,” said Byer, who is the recipient of the prestigious International Photography Award, in a press release. “I hope you’ll look deeply into these photographs and let them change your life too.”

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Write to Justin Worland at justin.worland@time.com.

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