I (37 years old) brought this book for a friends daughter (11) last christmas. When she opened the present she had read it already, many times and gushed about how brilliant it was.
Enthused she then gave me two of her favourite books to read, this one (Skellig) and Butterfly Lion. I dutifully took them and in spare moments read them.
I enjoyed Butterfly Lion but was just amazed at Skellig. It is one of those rare books that is most definately a childs book but adults will also marvel at the deft touches of tenderness and personality each character is given.
Being a big old grown up person I kind of guessed what the ending might offer but never expected it to affect me in the way it did, else I wounldn't have been sitting in a crowded pub reading it.
If your a kid make sure its on your list, if your a adult read it, it might just remind you how magical childhood is.