Incubus (Ballantine Reader's Circle) by Ann Arensberg

Dry Falls, Maine, was a simple farming town. Its residents lived innocently in sync with the seasons -- honest churchgoing folk who looked to the land for a living and to tiny St. Anthony's Church for spiritual sustenance. Until the spring of 1974, when a premature, blistering heat wave envelops the vicinity ... along with something far more sinister. As crops wither, livestock birth only deformed offspring, and husbands lose all desire for sex, an ancient, unholy evil hungry for lust, an Incubus, secretly begins to prey on the town's women. As one female after another falls victim to erotic nightmares and dark violations, Cora Leiber, the wife of St. Anthony's rector, must look for answers in the depths of faith -- and her own tormented soul.