She was 60. She was a hit on the folk scene, with Odetta, Jackson Browne, and Janis Ian in the early 70s. She never became a big hit, because she didn't like to tour.
Her daughter Valerie was born with hydrocephaly, which cause brain damage and Phoebe opted to stay home and care for her. She was not expected to live long, but died at age 31 in 2007. Phoebe had had a stroke in January and died of complications of the stroke.
Here are a few of her best works:
UPODATE: Rec list guys! Wow! First time. I am sorry that it is for such a reason. RIP Phoebe.