LOS ANGELES (AP) — Oprah Winfrey will have an in-depth conversation with famed author Isabel Wilkerson as part of the next episode of her “Oprah’s Book Club.”

Winfrey’s episode will focus on Wilkerson’s book “Caste: The Origins of Our Discontents,” which will air free on Apple TV+ on Friday. The detailed discussion will explore context of the book that delves into Wilkerson’s exploration of race and hierarchy in the U.S.

In the episode, Winfrey will also ask the reason behind writing “Caste” for Wilkerson, who won a Pulitzer Prize for her book “The Warmth of Other Suns.”

In August, Winfrey picked Wilkerson’s “Caste” for her book club.

Winfrey will dig deeper to discuss themes of the book in a two-part episode on Apple TV+ on Oct. 9.

“Caste” continues Winfrey’s book club partnership with Apple that began last fall. It includes previous picks such as Ta-Nehisi Coates’ novel “The Water Dancer” and the nonfiction “Hidden Valley Road,” by Robert Kolker.