Although a large body of research on hardiness (a personality construct with dimensions of commitment, control, and challenge) has accumulated, several fundamental issues remain unresolved. Although there are several hardiness scales, the properties of these scales have not been compared. There is debate as to whether hardiness is one or several characteristics. Research studying the pathways through which hardiness exerts its effects has not been comprehensively evaluated. Whereas critics have argued that hardiness does not buffer stress, others have suggested that hardiness buffers for working adults, for males, and in prospective analyses. There is also growing concern that hardiness is related to neuroticism. A review of the literature supports the following conclusions: The Dispositional Resilience Scale (DRS) has several advantages over alternative scales; DRS items form three factors that are consistent with hardiness theory; hardiness dimensions generally show low to moderate intercorrelations; the most common way of categorizing subjects as high or low in hardiness is not consistent with hardiness theory; hardiness does not buffer stress, and it does not buffer stress for working adults, for males, or in prospective analyses; both old and new hardiness scales inadvertently measure neuroticism. Recommendations for future research are provided.