Escape to Witch Mountain by Alexander Key USED

Condition: Former library copy so there is a stamp along pages. 

Summary: Some terrifying experience has blocked Tony and Tia's memory of the past. But because they have supernatural powers, they are sure that they come from another world--and that their people still exist somewhere.

Then Tony and Tia find that they must escape from men who want to use their special powers for evil. They begin a desperate search to find their true home--which leads them to the strange and mysterious Witch Mountain.