Oprah says she cried when she called author of "Caste," her latest book club pick: "All of humanity needs this book'

Oprah Winfrey has announced that "Caste: The Origins of Our Discontents" by Isabel Wilkerson is not only her latest pick for Oprah's Book Club, but that it "might be the most important book" she has ever chosen. 

"'Caste: The Origins of Our Discontents' provides a new way of seeing racial inequality, giving rise to countless 'aha' moments and helping us truly understand America as it is now and how we hope it will be," Winfrey said in a press release for the selection.  

The media mogul said she would be purchasing 500 copies of the book to send to mayors, CEOs and college professors around the country.

"All of humanity needs to read this book," she told "CBS This Morning" co-host Gayle King.

Penguin Random House, the book's publisher, called Wilkerson's work "a masterful portrait" describing the "rigid hierarchy of human rankings" that America has been defined by throughout its history. Wilkerson joined Winfrey and King for a conversation about her novel, and why she had "no choice" but to write it.

Read a portion of their conversation below:

Gayle King: I know you're excited about all your books, but this one is different because you're doing something that you've never, ever done before.

Oprah Winfrey: First of all, this is the 86th Oprah's Book Club selection… But this is the most important book, the most essential book —

King: Important with a capital 'I.'

Winfrey: The most necessary for all humanity book that I have ever chosen. The book is called "Caste" …by Isabel Wilkerson, not just Isabel Wilkerson, but Pulitzer Prize Isabel Wilkerson.

King: Hello, Isabel Wilkerson.

Winfrey: Isabel Wilkerson!

King: Give yourself a round of applause. Hello.

Winfrey: My heart sings just to see you here this morning.

King: So good to see you. Isabel, I was not exaggerating when I said I've never seen Oprah so excited when she said that she wants as many people as possible to read this book. She ain't playing. What are you doing?

Winfrey: I'm buying 500 books of my own and I'm sending them to every governor in the United States. I'm sending to the top 100 mayors in the United States. I'm sending them to the 100 top CEOs of companies —

King: College professors.

Winfrey: And college professors, the top 100 colleges.

King: And why are you doing that?

Winfrey: I'm doing that because I think, as I just said, 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 discontents and what "Caste" really means…so we haven't really given you a chance to speak.

King: Isabel, do you want to say anything?

Winfrey: Isabel, this book is the bomb!

King: …Because what's interesting about "Caste" is because I never thought of the U.S. as having a caste system. But after reading your book, I see it so clearly and I'm not sure I like what I see, Isabel. So explain — set the scene, set the tone for what you wanted to do in this book.

Isabel Wilkerson: This is not a book that I wanted to write…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… We have actually made so much progress when it comes to things that we consider to be traditional, old school racism of the Klansmen of, you know, the late-19th century and early 20th-century… And so now we are in a very different place. 

How is it that we have these situations in which there are these videos coming out  — so, so many that show African Americans, for example, moving about their regular day and someone comes in and then calls the police on them for sitting at a Starbucks waiting to be — waiting for their friends? How is it that we're seeing these things? There's something else that is percolating underneath all of what we can see.

Winfrey: What's so extraordinary is the comparison of the American caste system, the system in Nazi Germany and also in India. How did you come to that?

Wilkerson: Caste is something that we apply to India, the original caste system. So that was the first place I was going to look. And then after Charlottesville, Charlottesville pulled me into another direction, because in that moment we saw the symbolism of both the Confederacy and Nazi symbols coming together, converging, and the ralliers who had themselves made this connection. And that propelled me, inspired me, to go and look at the history of Germany. And how do they remember their past? What have they done in the intervening decades to reconcile that past and atone for it? And what can we learn from it?

King: One of the best things that I kept talking about to Oprah, I love the analogy of the house.

Winfrey: The house.

King: Talk about the house, Oprah, why we like that so much.

Winfrey: I want you to talk about the house.

King: Because it's so dead on.

Winfrey: The fact that you came up with that house as a metaphor for our country, and for me, it represents America as it has been, as it is and what it can be.

King: And everybody who has a house understands exactly what you mean…

Wilkerson: I present our country as an old house 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.

Winfrey: I have to say that the chapter on the euphoria of hate, that is the defining chapter for me, and you end that chapter by saying that 'It's much harder to look into the darkness in the hearts of ordinary people with unquiet minds needing someone to feel better than, whose cheers and votes allow despots anywhere in the world to rise to power in the first place. It's harder to focus on the danger of common will, the weaknesses of the human immune system, the ease with which the toxins can infect succeeding generations because it means the enemy, the threat, is not one man. It is us, all of us lurking in humanity itself.'

King: Drop the microphone, Isabel Wilkerson. There you go.

Wilkerson: That came after spending an entire afternoon in one of the many, many museums that have been set up in Berlin as ways to educate people about what had happened in hopes that it would never, ever, ever happen again… And it seemed to be that it connected all of the challenges that humanity has faced over time. And that is to the desire of impulse to divide and to rank and separate, and the need I think that we have now to transcend these false barriers and to see that we have so much more in common than we've been led to believe.

King: Can you just say this, what was it like when Oprah called you and said she'd chosen your book? …the phone rings, you pick up the phone.

Wilkerson: And it's the voice that is recognized all over the world.  

Winfrey: 'Hi, Isabel. It's Oprah.' But no, the first time I've called a book  — usually, I've called authors over the years and said, I'm going to choose your book. And sometimes authors cry and they're excited. It's the first time I called an author and I was crying.

King: Were you?

Winfrey: Yes.

King: You were crying when you called her?

Winfrey: I was crying because I'm so moved by this book, what you've done with this book, it's so amazing. Yeah, it's true. It's true.

King: Well, it's coming out. It's coming out [Tuesday, August 4]. I can't wait for people to read it.

Winfrey: All of humanity needs this book.

King: Thank you.

Winfrey: We need this book.

King: Thank you, Isabel Wilkerson, thank you. So nice to meet you.

Wilkerson: Thank you. Wonderful meeting you.

Winfrey: Can't wait to meet you in person.