Living systems maintain biologic equilibrium, homeostasis, by actively regulating different variables to remain within a certain range. Endogenous and exogenous stressors perturb homeostasis. The organism responds adaptively, to restore its equilibrium. This book explores the potential use of stressors to improve the adaptive capacity of organisms and expand their functional homeodynamic space. These endogenous (from within the body) and exogenous (environmental) stressors can be applied for: 1. Exercise Physiology (emphasis on hypergravity and resistance training) 2. Dietary Stress (emphasis on meal frequency, food restriction, and the use of plant toxins and other toxic chemicals) 3. Temperature Stress (emphasis on heat and cold stress) 4. Toxicology and Radiation 5. The field of Aging 6. Cognitive Stress and the concept of Anti-Fragility (a psycho-philosophical approach) The dose, frequency, and duration of exposure to a certain stressor or perturbing factor can turn it from advantageous (medication) to detrimental (poison). Reviewing the scientific literature and using personal examples (anecdotes), the author investigates dose-response relationships in an effort to develop practical strategies to benefit from deliberate exposure to physiologic and psychologic stressors.