Activist and author Susan Sontag died of leukemia on Dec. 28, 2004, at the age of 71. It was Sontag’s third bout with cancer since 1976, a disease that informed much of her writing in the last few decades.

Sontag was born Susan Rosenblatt in New York City, in 1933. Following the death of her father when she was five, the family lived in Arizona and Los Angeles, where her mother married an Army officer, Capt. Nathan Sontag.

After graduating from North Hollywood High School at 15, she attended...