Clinical Applications. The historical origins of Sigmund FreudÂs concept of the mechanisms of defense. The place of defense mechanisms in diagnostic formulation and in modern clinical practice. The need for a uniform nomenclature for defenses. The clinical management of immature defenses in the treatment of individuals with personality disorders. Empirical Studies. The struggle for empirical assessment of defenses. Empirical evidence that defensive styles are independent of environmental influence. An empirical study of defensive styles: the Defense Style Questionnaire. A cross-validation of two methods of investigating defenses. Toward reliability in identifying ego defenses: clinical techniques. An approach to evaluating adolescent ego defense mechanisms using clinical interviews. What do cross-sectional measures of defense mechanisms predict? A Q-sort approach to identifying defenses. Appendixes. Seven Assessment Schemes for Defense Mechanisms. DSM-III-R glossary of defense mechanisms. MeissnerÂs glossary of defenses. VaillantÂs glossary of defenses. PerryÂs Defense Mechanism Rating Scale. Ego Defense Mechanisms Manual (Jacobson et al.). BondÂs Defense Style Questionnaire (DSQ). VaillantÂs modification of the Haan Q-sort.