Early in psychologists’ study of the relationship between stress and health, a question arose about people who experience high levels of stress in their lives but do not suffer negative health consequences: What is it that enables some people not to get sick and even thrive under stress? Suzanne C. Kobasa (now Ouellette) proposed that peoples’ personalities make a critical difference for how they perceive and respond to stressful life events. Concerned that stress researchers painted a too-passive picture of people as victims of stress, she sought to understand individuals’ distinctive experiences and attempts to find meaning in the face of stress. She drew from existential philosophy and psychology and adult development research to propose the personality construct of hardiness as a buffer of the health-damaging effects of stressful life events. Kobasa characterized hardiness as having three components: commitment, control, and challenge. Commitment represents engagement in life and a view of experiences as meaningful, purposeful, and interesting; control is an individual’s effort to maintain some influence over what life brings; challenge is an orientation toward change as an inevitable and even rewarding part of life that is matched by an ability to be cognitively flexible and tolerant of ambiguity.