Ung's first memoir, First They Killed My Father: A Daughter of Cambodia Remembers, details her experiences in Cambodia from 1975 until 1980: "From 1975 to 1979—through execution, starvation, disease, and forced labour—the Khmer Rouge systematically killed an estimated two million Cambodians, almost a fourth of the country's population. This is a story of survival: my own and my family's. Though these events constitute my own experience, my story mirrors that of millions of Cambodians. If you had been living in Cambodia during this period, this would be your story too".