The letter was found by auctioneers in Edinburgh
A lost letter from Lawrence of Arabia, which mentions his move to Lincolnshire, is to be auctioned in Scotland.
The letter to Lord Rennell was found in a signed copy of Lawrence's book Seven Pillars of Wisdom which was brought into an auctioneers in Edinburgh.
The letter describes Thomas Lawrence's move to RAF Cadet College in Cranwell.
The book and autographed letter, which are valued at £28,000, are to be auctioned on 26 May.
In the letter, written in 1925, Welsh-born Thomas Edward (TE) Lawrence says: "Yes I'm here now... Lincolnshire is like a picture of dead earth in green & grey.
"The camp [RAF Cranwell] is good. Also the fellows, also the life. Mark me down for a further spell of quite happy existence."
He also dissuades Lord Rennell from buying the book in which it was found, saying: "You don't really want one, you know. Thirty guineas is an absurd price. Wash out the idea."
Simon Vickers, from book specialists Lyon & Turnbull, who are holding the auction, said: "The book, a signed copy of Lawrence's Seven Pillars of Wisdom, was brought in by the vendor, which is exciting enough as they are very rare.
"But it was when I was leafing through the book that I noticed the letter. It is a wonderful everyday letter from Lawrence."
Lawrence, who was born in Gwynedd and lived in Bovington, Dorset, left the RAF in 1935 and months later died in a motorcycle crash near his home.
The Seven Pillars of Wisdom was published privately in 1926.