Twins (Point Horror) by Caroline B. Cooney - Vintage Paperback

Two girls . . . one life.

Mary Lee and Madrigal are identical twins, exactly alike in every way. Mirror images. Two halves of one whole. Or so it appears.

Until they are separated, leaving Mary Lee lost and alone. And Madrigal more beautiful, more popular, and happier than ever. . . with a boy who loves her.

Mary Lee wishes she could live her sister's life. But when her wish comes true, Mary Lee is horrified to find out that Madrigal was not the person she seemed to be.