A brief history of the underlying principles of the conventional fractionation in radiation therapy is discussed, followed by the formulation of the hypothesis for hypofractionated stereotactic body radiation therapy (SBRT). Subsequently, consequences of the hypothesis for SBRT dose shaping and dose delivery techniques are sketched. A brief review of the advantages of SBRT therapy in light of the existing experience is then provided. Finally, the need for new technological developments is advocated to make SBRT therapies more practical, safer, and clinically more effective. It is finally concluded that hypofractionated SBRT treatment will develop into a new paradigm that will shape the future of radiation therapy by providing the means to suppress the growth of most carcinogen-induced carcinomas and by supporting the cure of the disease.