This chapter introduces the nomenclature, presents the anomolous nature of isolated data from radiation hormesis, and reviews the author’s introduction to this phenomenon. It summarizes the extensive information base for the general thesis, states the general thesis and provides the series of experiments in which results obtained were predicted by the thesis. Hormesis is the positive stimulation by subharmful quantities of any agent to any system. The word was first used by Southam and Ehrlich to designate the stimulation of fungal growth by low concentrations of oak bark extracts that inhibited fungal growth in physiologic doses. Hormesis involves a changed reaction of an organism to suboptimal conditions. The extensive literature on radiation stimulation of plants supports the limited data from animals and provides guidance for practical development. Hindsight allows hormesis to explain the anomalous results, and foresight recommends judicious experimental design and interpretation of data to utilize another facet of nature.