In 1990 we advanced the hypothesis that frightened and frightening (FR) parental behavior would prove to be linked to both unresolved (U) adult attachment status as identified in the Adult Attachment Interview and to infant disorganized/disoriented (D) attachment as assessed in the Ainsworth Strange Situation. Here, we present a coding system for identifying and scoring the intensity of the three primary forms of FR behavior (frightened, threatening, and dissociative) as well as three subsidiary forms. We review why each primary form may induce fear of the parent (the infant's primary "haven of safety"), placing the infant in a disorganizing approach-flight paradox. We suggest that, being linked to the parent's own unintegrated traumatic experiences (often loss or maltreatment), FR behaviors themselves are often guided by parental fright, and parallel the three "classic" mammalian responses to fright: flight, attack, and freezing behavior. Recent studies of U to FR, as well as FR to D relations are presented, including findings regarding AMBIANCE/FR+. Links between dissociation, FR, U, and D are explored. Parallel processing and working memory are discussed as they relate to these phenomena.