Over the past 20 years there has been increasing interest in the concept, psychological hardiness. Hardiness is defined as a constellation of attitudes, beliefs, and behavioral tendencies that consist of three components: commitment, control, and challenge. The article presents a review and assessment of more than 50 journal publications on hardiness that have appeared since 1987. A presentation of the conceptualization of hardiness and the state of the science of hardiness is presented. Limitations in the current science of hardiness are delineated. These limitations include the identification of: factors related to conceptualization and instrumentation, the types of hardiness studies lacking in the current literature, and the types of subjects rarely used in hardiness research.