Personality assessment in adolescence requires a twofold task. On one side it has to provide a clinical useful assessment, taking account of both pathological and healthy features, and treatment implications. On the other hand, it has to provide a distinction between "emerging" patterns vs relatively enduring dysfunctional personality traits and characteristics. Personality assessment, particularly in adolescence, requires empirically grounded and methodologically reliabile instruments and classification systems that are also clinically sophisticated and useful. According to this perspective, the Editors of this issue of "Infanzia e Adolescenza" have collected three papers focused on clinical and empirical aspects of two new diagnostic instruments--the Psychodynamic Diagnostic Manual (PDM) and the Shedler-Westen Assessment Procedure 200-Adolescent (SWAP-200-A). Because personality disordes result from the combination of many developmental factors, the Editors decided to include one research-paper focused on the relations among proactive and reactive dimensions of aggression, overt and covert manifestations of narcissism, and styles of moral reasoning. Eventually, one paper consists of a 20 years follow up study on comorbidity of Axis I and Axis II disorders in early adolescence.