A fourth writer has been added to the lineup of this fall’s Talking Volumes book club, which features an all-woman, all-nonfiction lineup. Isabel Wilkerson, the Pulitzer Prize-winning author of “The Warmth of Other Suns,” will speak about her new book, “Caste: The Origins of Our Discontent.”

The interview with Wilkerson, at 7 p.m. Oct. 13, will close out the Talking Volumes season. Her book is an examination of the caste system as a way for systemic racism to flourish in the United States as well as in other countries, including India and Nazi Germany.

The other Talking Volumes speakers are Claudia Rankine, prizewinning author of “Citizen” and “Just Us: An American Conversation,” who will open the season Sept. 22; Helen Macdonald, author of “H Is for Hawk” and the new essay collection “Vesper Flights,” on Sept. 30, and Sarah M. Broom, author of the prizewinning memoir “The Yellow House,” on Oct. 6.

Tickets are on sale now for the four lectures, which will take place via Zoom in this year of COVID-19. Tickets this year are pay-what-you-can, available at MPRevents.org.

The appearance of novelist Yaa Gyasi, previously announced for Sept. 17, was canceled due to a scheduling conflict. She will speak in February as part of Hennepin County Library’s Pen Pals lecture series.