Everybody’s gotta start somewhere. For the 19-year-old formerly known as Barbara Joan Streisand, that somewhere was Bon Soir, an intimate nightclub in New York’s Greenwich Village, where her performances heralded the arrival of a major new artist. Correspondent Mo Rocca talks with author James Gavin and critics Wesley Morris and Stephen Holden about Barbra Streisand’s debut, and how New York’s cabarets in the 1950s and ’60s helped launch some of the most influential figures of American popular culture.