LOS ANGELES, July 3 -- The week doctors told her she needed a new set of lungs or she would not survive it, Muni Long was somewhere between cities on a tour bus, far from any surgical ward where that calculation could be acted on immediately. Pneumonia had found her while she was working Brandy and Monica's run, and by the time it had moved through an immune system already weakened by twelve years of lupus management, the window for alternatives had closed to approximately seven days.

Six months after the double lung transplant that followed, Long released "Richest," a new song featuring rapper Akeem Ali that marks her first music since the surgery. The two-time Grammy winner had been absent from the industry long enough that the return ...