A close associate describes Dana Reeve as "a woman with an incredible heart."
The 44-year-old died last night of lung cancer at a New York hospital.
The president of the Christopher Reeve Foundation says Dana Reeve "really put herself out there to help" people with disabilities and caretakers. Kathy Lewis says she visited Reeve in the hospital Friday and she "was tired but with her typical sense of humor and smile."
Four months ago at a fund-raiser for the foundation, Reeve said she could stay in good spirits because of the model set by her late husband. She described him as "a man who never gave up."
The star of the "Superman" movies became an activist for spinal cord research after a horse-riding accident paralyzed him in 1995. He died in October 2004.
His wife was a constant companion and supporter during his ordeal.
They had a 13-year-old son.