This chapter focuses on the assessment phase and importance of negative cognitions (NCs) drawing heavily on illustrative case vignettes. Janoff-Bulman introduced the notion of an “Assumptive World Theory” to describe how individuals make assumptions about themselves and the world they live in. According to McCann and Pearlman’s Constructionist Self-Development Theory (CSDT), people give meaning to traumatic events depending on how, as individuals, they interpret them. Person-centered counseling refers to “self-concept” describing the individual’s self-image largely based on life experience and attitudes expressed by significant others, such as family, teachers, and friends. Therapists should familiarize the client at an early stage with the mechanics of DAS and allow them some control in choosing the technique to be used. In choosing the target memory, the therapist and client need to determine the touchstone event, that is, the earliest memory linked to the current pathology.