The principles of the redox code (Figure 4) provide a basis for a new interpretation of aging. The redox metabolome and redox proteome provide an important interface between an individual and his/her environment [6]. An increase in atmospheric O2 enhanced the magnitude of the intracellular/extracellular redox gradients and provided driving forces for multicellular differentiation and evolution of complexity in metazoan speciation. Genetic systems evolved programs to support this speciation, with the important characteristics that the systems provided memory systems to facilitate adaptation to environment during the lifespan of an individual. Within the overall redox network structure, accumulation of adaptive responses during development and lifelong exposures results in decreased adaptability over time. Aging is the decline in adaptability due to irreversible characteristics acquired in response to exposures during differentiation, maturation, and subsequent adult life. From [1].