Both Sides Now

In which Joni Mitchell, one of America's most respected singer-songwriters, rents an orchestra and tries her hand at some standards, including two of her own. It's tough to argue with the spirit of the set, a song cycle tracing the arc of love gone wrong highlighted by ''You're My Thrill'' and ''You've Changed'' (both associated with latter-day Billie Holiday), a ripe re-visioning of ''Blue's'' ''A Case of You,'' and a take on ''Both Sides Now'' that benefits from her vocal maturity. But Mitchell's art is about her writer's voice more than her interpreter's voice, and in the end, this is more curio than keeper.