New morphologic evidence in human temporal bones from patients with vestibular neuronitis, Ménière's Disease, benign paroxysmal positional vertigo, and idiopathic facial paralysis is put forward to support the concept that these neuropathies are caused by re-activation of a latent neurotropic virus (Herpes family) located in the sensory ganglia. Previously unreported changes indicate that the efferent neuronal pathways to the auditory and vestibular end organs may degenerate as a result of their course through the inflamed vestibular ganglion. Such paralysis of the efferent system may be responsible for secondary symptoms (tinnitus, motion intolerance) associated with these neuropathies. Case histories with magnetic resonance imaging of the seventh and eighth cranial nerves are described in support of the viral neuropathy concept. In conclusion, some thoughts on the limitations and effectiveness of antiviral therapy are presented. The book provides an explanation for understanding and treating the various symptoms associated with vertigo and idiopathic facial paralysis for all clinical specialists who treat patients suffering from these disorders.