Two theories on stress are introduced. The first one proposes the unification of the two great research traditions on stress, biological and psychological, within a systemic science, psychoneuroendocrineimmunologic, aimed at both explaining the complex interaction between different levels of stress incidence on health and disease, and integrating the care of the others and the care of oneself. The other theory, oriented towards the study and the improvement of human being's condition, especially well-being at work, criticizes the psychological interpretative perspectives. According to this theory, stress is conceived as a psychoneuroendocrineimmune process, while health and prevention are seen as perfectible processes. Several differences, compatible elements as well as synergies between the two theories emerge
