Brian Greene is a theoretical physicist, mathematician, and string theorist. He has been a professor at Columbia University since 1996 and chairman of the World Science Festival since co-founding it in 2008. His new book "Until the End of Time" is now available: https://amzn.to/2ug680o
Daryl Davis is an R&B and blues musician, activist, author, actor and bandleader. He also is the author of "Klan-destine Relationships: A Black Man's Odyssey in the Ku Klux Klan".