The clinical approaches to the chronic degenerative diseases that drain our resources, and compromise our well-being, have become almost exclusively symptom-focused. The common wisdom is that they are idiopathic with final outcomes to be managed rather than prevented or cured. That they are potentially reversible rarely enters any discussion between doctor and patient. Reversibility of Chronic Disease and Hypersensitivity, Volume 5: Treatment Options of Chemical Sensitivity, the final volume of this set, offers a much different perspective on chronic degenerative disease; one that disputes the idiopathic label attached to most, as well as the usual fatalistic prognosis.