A collection of letters sent to children by CS Lewis have gone on sale.
The 29 letters were sent by the Chronicles of Narnia author to an American family of eight siblings who had written to ask about his books.
The writer corresponded with the Kilmers between 1954 and 1963 and discussed his characters, religious beliefs, and advice on life.
Historical document dealer the Raab Collection is now offering them for sale for $110,000.
The letters formed the core of the book Letters to Children, published in 1985.
Lewis dedicated the sixth volume in the Narnia series, The Magician's Nephew, to the Kilmer family, who lived in Washington DC.
In one he wrote: "You must have often wondered how the old Professor in The Lion, W.W. could have believed all the children told him about Narnia.
"The reason was that he had been there himself as a little boy."
He said The Magician's Nephew would explain "how he went there" and "how the White Witch first got into that world and why there was a lamp-post in the middle of that forest".
Raab Collection president Nathan Raab said: "These letters show a rare and powerful side of the great writer, and also the importance to him of mentoring the next generation."
The Chronicles of Narnia series has sold more than 100 million copies worldwide and been adapted into three films and a TV series.
Belfast-born Lewis was an Oxford University fellow and tutor at Magdalen College and lived in Headington for more than 40 years.