Oprah called her latest book club pick "Caste: The Origins of Our Discontents" by Isabel Wilkerson her most important selection yet.
CNN  — 

Oprah says her latest book club pick “might well save us.” So the media mogul is sending 500 copies to the nation’s governors, mayors, CEOs and college professors.

The book is “Caste: The Origins of Our Discontents,” written by Pulitzer Prize-winning author and journalist Isabel Wilkerson. Oprah announced on Tuesday that it was her latest selection for her long-running book club – and that it was the most important one yet.

“This is a book for all of humanity and it is necessary for people who are leaders in our country to understand the origins of our discontent and what caste really means,” she said on “CBS This Morning,” adding that she was sending the book to leaders across the nation.

“Caste: The Origins of Our Discontents” examines race in the United States as a social hierarchy, with African Americans confined to the bottom. The book defines racism in the country as an American caste system, comparing it to social hierarchical systems in India and Nazi Germany.

“Caste and race are neither synonymous nor mutually exclusive. They can and do coexist in the same culture and serve to reinforce each other,” Wilkerson wrote in an essay for The New York Times Magazine, adapted from her book. “Race, in the United States, is the visible agent of the unseen force of caste. Caste is the bones, race the skin.”

Wilkerson spoke Tuesday to Oprah and CBS News journalist Gayle King about her latest work.

“This is not a book that I wanted to write,” she told Oprah and King. “This is a book that compelled me, that called to me, that I felt I had no choice but to write it. And so I ended up working on this because it seemed that there were things going on that only caste could really explain.”

Wilkerson explained that though the United States has made significant progress since “traditional, old school racism” such as the Ku Klux Klan and the Jim Crow era, issues of racism persist today in other ways.

“I present our country as an old house,” Wilkerson explained. “And when you have an old house, you know that there’s always work to be done on it. And when after a rain, you do not want to go into that basement sometimes because you don’t want to know what you might face there, but whatever is there, you’re going to have to deal with, whether you wish to or not. It’s never going away until you address it.”

Wilkerson is the author of “The Warmth of Other Suns,” which won the 2010 National Book Critics Circle Award for nonfiction. The book tells the story of African Americans migrating from the South to the Midwest, Northeast and West during the 20th century.

President Barack Obama awarded Wilkerson the 2015 National Humanities Medal. And in 1994, Wilkerson became the first Black woman to win a Pulitzer Prize in journalism. She was recognized for her profile of a Chicago fourth-grader and for two stories about a Midwestern flood, according to the National Association of Black Journalists.

“Caste: The Origins of Our Discontents” was published on Tuesday.