Enter the enchanted world of Earthaven...
There are currently two books in this series, although I keep thinking I should add another - Spell Summer, perhaps? The first book Spellfall became my debut in America, published by Scholastic US and launched in style at the American Libraries Association conference in San Francisco.
Spellfall has a long history in print. You might see some of the original covers in archived posts on this blog. Here are a few related posts:
Tricks and treats in Unicorn Wood - a unicorn's view of Spellfall.
Do young readers prefer paper books? - my first venture into print on demand paperbacks at Createspace (now part of Amazon's KDP).
Ten Things you can't do with a Kindle - the argument for paper books, over at The History Girls blog.
Ten things you can do with a Kindle - that you can't do with a paper book!
The computer recommends - a snapshot of the 'also bought' lists on Amazon for Spellfall and a couple of my other books.