Opera: Presto Change

There is nothing like a change of key to unlock a whole new career. At least such is the case of a tall Welsh lass named Gwyneth Jones. A year and a half ago she was a so-so mezzo, beset with a special problem: "My voice just kept going up and up." Why fight it, she thought. So presto change, the mez zo became a soprano.

Almost immediately her stock as a singer also soared up and up. She was signed by London's Royal Opera and two months ago awarded her first major role in Covent Garden as Leonore in...