Members of the 14th Flying Training Wing wait in line during a book signing Jan. 10, 2020, at the Columbus Event Center on Columbus Air Force Base, Miss. Retired Air Force Col. Carlyle “Smitty” Harris, originally from Preston, Maryland, now living with Louise in Tupelo, Mississippi, released a book titled “Tap Code: the Epic Survival Tale of a Vietnam POW and the Secret Code That Changed Everything.” (U.S. Air Force photo by Airman 1st Class Hannah Bean)