Children develop within the context of caregiver--child relationships, each presenting with their own unique strengths, areas of growth, and compatibility of fit. Instead of the traditional viewpoint that child symptoms are generalizable across contexts and would emerge across relationships, the DC:0--5™: Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood™ (DC:0--5; ZERO TO THREE, 2016, 2021) manual provides the ability to capture emotional or behavioral challenges that only exist within the context of one relationship. The article is excerpted and adapted from the forthcoming "DC:0--5 Casebook" (Mulrooney et al., in press). The Casebook is a compilation of case studies as a companion volume to "DC:0--5™: Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood" (DC:0--5; ZERO TO THREE, 2016, 2021).