Ghost School

Ghost School is a book by Eth Clifford. It was published in 1998.

Summary
Elizabeth, her twin sister, Carol, and their friend Jeff have a plan to spy on a haunted schoolhouse. Everyone has heard that there are ghosts in the old building, but the three kids decide to see for themselves.

The Ghost School is full of lessons in vanishing and history lessons with famous ghosts like the Headless Horseman! But when the kids meet up with the ghost principal, they find that he needs their help -- and fast!