The Book of Fire — David L. Dawson

On a world where 99.9 per cent of the population have magic Cressida Widdershins often feels left out because she's about as magical as a turnip. But when a school trip presents her with a magic book she feels her time has come. Unfortunately dark forces are also after the book; shadow beings with vast powers and their assassin, a man who can turn people to stone. The phrase "be careful what you wish for" springs to mind...
This version contains the 3 books of The Book of Fire Trilogy (Fire, Shadow and Ice), a fully edited and expanded edition of the original novel The Book of Fire.
This is the first volume in the Cressida Widdershins series.
I'd recommend it for children aged 10 and up, and for anyone who loves Harry Potter.