Biggles Does Some Homework

The author died while on chapter 12 of this adventure and the book remained unfinished and unpublished for 30 years after his death. The exact plot is not known to me.
Biggles is 65 and at normal retirement age but his love of adventure and companionship with his friends has not diminished. One of the things facing Biggles in the newly expanding Special Air Service is who might replace him.