Vu Dinh Son was 18 months old when his father left home to fight American forces in Vietnam, and just 2 when the man was killed in a foxhole encounter with U.S. Marines. But the son now has fresh glimpses into the life of the father he never knew thanks to a wartime diary, returned to him courtesy of the United States.

The pocket-sized book was brought to Vietnam in June by Defense Secretary Leon Panetta, who, in return, was handed a bundle of letters written by an American soldier that had been kept in Vietnam. The high-level exchange of artifacts symbolized a joint desire for closer ties by the former enemies, who now share concerns over China's rise.

U.S. Marine Robert "Ira" Frazure took the diary from the chest of Son's father, Vu Dinh Doan, in March 1966 and then took it home with him, presumably as a war souvenir. Earlier this year, he asked the sister of a fellow Vietnam vet to track down Doan's family in Vietnam to return the diary. She did that with the help of the PBS television program "History Detectives," which tracked down Doan's family earlier this year.