A pair of letters by the inventor of the bouncing bomb, Sir Barnes Wallis, will be sold at International Autograph Auctions on March 5.
Each is valued at £200-300 ($282-424).
The letters were written to a friend in December 1944, shortly after his bomb was used in the first raid, and in May 1945.
In the first letter he writes: "It was not until I had had time to relax that I realised how utterly tired out I was.
"For the past year I have had to force myself to go on; & I must have been as near a crash as one would care to go."
A set of medals awarded to Dam Buster Flight Lieutenant Trevor-Roper realised a record £148,000 last year.
Please sign up to our free newsletter to receive exciting news about autograph auctions.