Significant advances have occurred in our knowledge of the effects of maltreatment on the developmental process since the “battered child syndrome” (Kempe, Silverman, Steele, Droegemueller, & Silver, 1962) was first identified. In fact, during the mid-1980s and onward, the quality and methodological sophistication of investigations of the developmental sequelae of child maltreatment increased dramatically (for summaries, see Cicchetti & Lynch, 1995, and Cicchetti & Toth, 2000). However, overall progress has been hampered by a lack of consensus on the operationalization of the construct of child maltreatment (Barnett, Manly, & Cicchetti, 1993; Besharov, 1981; Cicchetti & Rizley, 1981; Giovannoni & Becerra, 1979). In recognition of the complexities accompanying definitional issues in the area of maltreatment, a decade ago a Special Issue of Development and Psychopathology was devoted to defining psychological maltreatment (Cicchetti, 1991). The challenges associated with defining maltreatment were again highlighted in a Special Issue of Development and Psychopathology that addressed advances and challenges in the study of the sequelae of child maltreatment (Cicchetti, 1994a). In the editorial to that issue, Cicchetti (1994b) concluded that “the lack of consensus regarding the definition of maltreatment employed by various investigators [had] made comparability across studies difficult to achieve” (p. 2).