LIVING DEAD GIRL by Elizabeth Scott

When Alice was 10 years old and on a field trip with her class, Ray took her.  He threatened to kill her parents if she told anyone.  So Alice and Ray live together, pretending to be father and daughter.  It is now 5 years later, and despite near starvation, Alice no longer looks like a little girl.  So Ray decides that Alice will help him get another little girl to take her place. 

Told through the character of Alice, this is a rather disturbing novel about child abduction and sexual abuse.