From Lewis's letter and the dedication to The Lion, the Witch and the Wardrobe.

"My Dear Lucy,

"I wrote this story for you, but when I began it I had not realized that girls grow quicker than books. As a result, you are already too old for fairy tales, and by the time it is printed and bound you will be older still. But some day you will be old enough to start reading fairy tales again. You can then take it down from some upper shelf, dust it, and tell me what you think of it. I shall probably be too deaf to hear, and too old to understand a word you say but I shall still be,

your affectionate Godfather,

C. S. Lewis.

Book: Letters of C. S. Lewis