The Spook's Apprentice: Book 1 by Joseph Delaney
A wonderful and terrifying series by a new writer about a young boy training to be an exorcist. Thomas Ward is the seventh son of a seventh son and has been apprenticed to the local Spook. The job is hard, the Spook is distant and many apprentices have failed before Thomas. Somehow Thomas must learn how to exorcise ghosts, contain witches and bind boggarts. But when he is tricked into freeing Mother Malkin, the most evil witch in the County, the horror begins ...