The Boggart by Susan Cooper

A Boggart is a mischevious spirit that likes to play tricks in this delightful tale by Susan Cooper. It has lived for generations in an old castle in Scotland playing tricks on the various occupants of the castle. When the current occupant, an old man, dies, the castle is inherited by relatives in Canada. After they travel to Scotland to look at the castle and decide what to do about it, the boggart gets trapped in a desk being sent to Canada with some of the castle furniture. Once in Canada, the Boggart begins to play its tricks on the Volkert family, including Emily and Jessup, the two children. When a psychologist begins to blame all the mysterious happenings on Emily creating a poltergiest with psychokinetic energy, things get tricky. It's up to Emily and Jessup to figure out what is going on and how to solve the problem of the Boggart with a decidedly modern day solution. The Boggart by Susan Cooper. Aladdin Paperbacks, 1993.