Three signed first edition copies of books by C.S.Lewis, the Watford-educated author of The Chronicles Of Narnia, are expected to fetch up to £3,000 each at an auction next month.

The books - The Voyage Of The Dawn Treader,The Horse And His Boy and The Last Battle - have been put up for sale by Lewis's friend and former private secretary, American-born Walter McGehee Hooper, 77, who plans to give the proceeds to a Roman Catholic church in Oxford, where C.S.Lewis worked and spent much of his life.

The books,which will be auctioned at Sotheby's in London on July 17, are particularly valuable because they are first edition copies and all three are signed by C.S.Lewis.

This year marks the 110th anniversary of C.S.Lewis's birth. He was born in Belfast in 1898, but moved to Watford at the age of nine following the death of his mother, Florence.

Within two weeks of her death he joined his older brother, Warren, at Wynyard House, a Watford preparatory school.

Lewis later described the school as "a concentration camp”.

According to Lewis expert, Peter Schakel, in The Literary Encyclopedia: "The school's headmster was tryannical and abusive (though the Lewis boys were spared from beatings). Lewis's attitude towards schools, expressed frequently in his fiction and non-fiction, was shaped by his unhappy experience at Wynyard."

After leaving Watford, C.S.Lewis went on to write The Chronicles of Narnia, seven works of fantasy produced for children and published between 1950 and 1956. The books have since been translated into more than 30 languagues and sold millions of copies.

At least two titles from the series -The Lion,The Witch and The Wardrobe and Prince Caspian: The Return To Narnia - have been adapted for films.

Clive Staples Lewis, affectionately known as Jack, died on November 22,1963 - coincidentally, the day US president, John F.Kennedy, also known as Jack, was assassinated - just a week before what would have been his 65 birthday.

In his will,he left £55,869.That might not sound a lot now but in 1963 that sum would have been enough to buy 17 decent houses in Watford, as the average house then cost £3,160.