Cecil Harris, author of the books Different Strokes and Charging the Net about black tennis history, rejoins Thirty Love host Carl Bialik to talk about his sense that the Williams sisters will retire in 2020, why young African-American men aren't picking up tennis racquets, and where the Black Tennis Hall of Fame should make its home. Have a suggestion for a Thirty Love guest? Email Carl at bialik@pm.me Music by Lee Rosevere: "Credit Roll" and "Glass Android."