Beyoncé, ‘I Am … Sasha Fierce’: Aidin Vaziri | Beyoncé Knowles has finally lost her mind. No, really. “I have someone else that takes over when it’s time for me to work and when I’m onstage, this alter ego that I’ve created kind of protects me and who I really am,” she says. “Sasha Fierce is the fun, more sensual, more aggressive, more outspoken side and more glamorous side that comes out when I’m working and when I’m on the stage.” But even her alter ego is suffering from an identity crisis. “I Am … Sasha Fierce” is a double album with two distinct sides. The first half is made up of midtempo pop tunes written by Amanda Ghost, one of the collaborators behind James Blunt’s “You’re Beautiful.” These are supposed to represent the real Beyoncé and are, therefore, quite dull. Well, aside from the single “If I Were a Boy” and the reasonably genius “Halo.” The second half, meanwhile, is made up of futuristic R&B jams produced by Bangladesh and Jim Jonsin. All computer beats and minimalist melodies, they are breathtakingly risky for a singer who too often plays it safe. But the risk pays off, and not just because tracks such as “Radio” and “Video Phone” sound as if they were swiped from Björk. The staggering “Single Ladies (Put a Ring on It)” is one of the best things Beyoncé’s ever done – under any of her personalities.