I think this is technically a children's book, Walker Books certainly specialises in publishing for children, and there's something about the illustrations that suggest that it's meant for younger readers, but there's nothing about it that isn't equally satisfying for the adult reader as well.
I had this on my wish list and a really wonderful friend (she has a habit of picking the books I most want off that list) bought it for me at Christmas - I've been enjoying it a few stories at a time ever since.
There's a quote on the back of the book from Philip Pullman that simply says "This great storyteller", and I can think of no better words to describe Kevin Crossley-Holland. What makes this collection so good (for young and old alike) is the way that he strips the stories back to their basics and then adds just the right amount of personality and poetry to make them not just come alive, but to sing for the reader.
Some are barely a couple of paragraphs long (Boo is particularly good - a nervous young woman alone in her fathers house secures doors and windows with all possible diligence, only to hear a voice say 'That's good - now we're locked in for the night' - how can a ghost story get better than that?) most run to a few pages, and there are some like Tam Lin which stretch a bit further.
There's everything here from tales of fairies, to ghost stories, taking in adventurous epics, love stories, and battles of wits along the way. Some feel ancient, others sound like they might be more modern in origin - but they're all good, and the long twilight of midsummer is my favourite time of year for stories like this. It's a time when anything sounds like it might be true and you can never be quite sure of what you're seeing. I can think of nothing better to read by the dying embers of a campfire (even if it's only at the bottom of the garden) at the end of a day.