Richard Matheson picked and chose the most effective elements of such earlier films as Rosemary's Baby and The Exorcist, then glossed over all with his own original touch. The result was this superior (if occasionally wavering) TV movie. Barbara Eden, who after five years of I Dream of Jeannie was no stranger to the supernatural, is here cast as a mother-to-be whose baby is inducing more than the standard kicks and labor pains. Fact is, the little stranger in the womb is an extraterrestrial being, bent upon controlling Eden's body and mind. The Stranger Within should not be watched in a natural-childbirth class anywhere at any time.