Barbra Streisand has been such a force on the entertainment scene for so long (her 1963 debut album, recorded when she was just 20, won an Album of the Year Grammy) that a glimpse back at her first years in show business offers fascinating insights into her evolution as a performer, and a person. Here, LIFE.com offers a window into the intense, emotionally fraught world Streisand inhabited and, in a sense, created for herself with her own outsized insecurities and perfectionism early in her career.
In 1966, for example, LIFE published a cover story on the then-23 year old Brooklyn native that portrayed the young star as a "fear-ridden girl" terrified that her early success "could suddenly all fall apart." Of course, creative people who have enjoyed (or endured) fame right out of the gate almost invariably, at one point or another, suffer lacerating self-doubts; Streisand, however, appears to have examined her own talents and achievements with the same tenacity that she brought to, say, mastering the nuances of a new tune or the timing of a comedic line.
"Why Barbara Streisand has to know what people think of her every time she performs is an astounding, and wrenching, phenomenon," wrote LIFE's Diana Lurie in the March 18, 1966, issue of LIFE. "At 23, she is an undisputed queen of musical comedy, television and records. Every one of the seven records she has made sold a million copies. She gets $50,000 per concert appearance. For nearly two years she pulled in standing room-only audiences for an otherwise undistinguished musical, Funny Girl. . . . Everybody knows Streisand is on top. So does she. And the more she is hailed, the more scared and unsure she feels. 'I win awards and everything but one of these days something is going to bomb. It's a scary thing.'"
Even more surprising in the LIFE cover story is the assertion that, while "her audiences adore Barbra," she "looks on them as her adversaries." During taping of a TV special, hyper-critically watching her own performance played back on monitors, she told her agent: "I know this is a better show than the first. But they are waiting for it to bomb. They always are. People say, 'Go and see this terrific girl.' But most of them come thinking, 'Nah, she can't be that great.' It makes me feel they're the monster and I'm their victim."
Despite—or perhaps because of—this deeply ambivalent attitude toward her audience and her triumphs, Streisand also displayed a cool, collected and (for a 23-year-old) remarkably astute understanding of her own stardom.
"My success? The only way I can account for it is that whatever abilities other performers have, I must have it plus. Onstage I am a cross between a washwoman and a princess. I am a bit coarse, a bit low, a bit vulgar and a bit ignorant. But I am also part princess—sophisticated, elegant and controlled. I can appeal to everybody."
Then, she adds: "When I am not performing, however, I don't think I have that definite a personality. I think maybe I have nothing."
Maybe I have nothing. All these years later, after the Emmys (five), Oscars (two), Grammys (eight) and a special Tony Award; after selling millions upon millions of records, filling concert halls and arenas and enjoying the undying devotion of countless fans the world over—after all that, one can only hope Streisand has come to embrace the notion that, just maybe, she does have something after all.
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter at @LizabethRonk.