At the height of the Great Depression, scores of US citizens found themselves homeless and without work. In the Midwest, dramatic changes in the landscape caused by over-farming created the dust bowl that destroyed entire regions of farmland and resulted in a mass exodus of nearly 2.5 million Americans from the Plains states.

To combat this trend in rural poverty, the Farm Security Administration was created as part of president Franklin D. Roosevelt’s New Deal programs. Central to their work was a team of 11 photographers who were dispatched across the US to document the state of rural America and provide photographic evidence to Congress on the living conditions of farmers.

In 1976, the book A Vision Shared: A Classic Portrait of America 1935–1943 brought together these pictures for the first time in a way that was accessible and concise. For the 40th anniversary reissue of the book, its author, Hank O’Neal, has shared with BuzzFeed News some of the most iconic pictures made by the FSA and his words on the legacy of the program’s photographers.

These were photographs that were made for a purpose, and often that purpose saved lives and made life better for people. It was to help raise Americans out of the circumstances that they found themselves in, and to do that, the FSA brought together what was easily the finest group of photographers ever assembled in the United States, if not the world.

And it’s remarkable that it all worked out, too, because there were people at the time who wanted to shut the program down. They didn’t want to show Americans depicted like this. There were people who wanted to burn the files, to destroy these pictures and their negatives, everything.

The most famous picture from the series is Dorothea Lange’s the “Migrant Mother.” The backstory about that, which is rarely told, is that Lange was driving home to Berkeley, California, when she looked out the window of her car and she saw a migrant camp over on the side of the road. She thought to herself, I wonder what that’s all about, and drove in, only to discover something really quite horrible. What she learned was that an early frost had wiped out the pea crop and the farmers essentially had no work and were starving — some to starving to death.

She said that something drew her to a certain tent in the camp, where she found a lady with her seven children. The family had sold the tires on their car to buy food, which was running low. They were essentially stuck.

So Lange took a handful of pictures of that woman, one of which became her iconic portrait, the “Migrant Mother.” She then drove home to Berkeley as fast as she could, developed the pictures, and sent them to the paper to be published. After the pictures ran, relief supplies were at the camp within two days! That’s the true power of these pictures.

Many of the problems facing the people in these pictures are still occurring today. There was a terrible stock market crash in 1929, which put so many people out of work, as well as some serious climate change issues occurring at the time. Of course, they didn’t call it climate change back then, but it was the beginning of understanding what climate change actually meant.

It was during this era that the Dust Bowl formed in the Midwest, pushing all these people who once owned farms toward the West in hopes of starting new again. Today, it’s ironic to think that California is worried about migrants coming in from Mexico, when in the 1930s they were trying to stop migrants from coming in from Nebraska!

It was tough times. Fortunately, these pictures made a difference.

During my research of the book, I found at the bottom of a file cabinet in the Library of Congress a bunch of index cards that had been filled out by people who had seen the first exhibition of these pictures in 1938 at New York’s Grand Central Station. A couple hundred of those cards are transcribed in the back of the book and express how people felt about seeing these pictures for the first time. The comments range from “This isn't America!” and “These people are all communists!” to “These pictures are going to change the world.”

With this reissue, I hope that a whole new generation sees these pictures within the context of the times and realizes the importance of a strong image and the impact it can have in helping people. I want people to continue making pictures with such power, and really, because with the way the internet works, a news organization can make a profound impact through photography at a faster rate than any of the FSA photographers could have imagined.

To learn more about A Vision Shared — A Classic Portrait of America 1935–1943 and to pick up your copy, visit steidl.de.