Clinicians working with traumatized youth face many challenges in supporting growth and development while addressing the many negative consequences of abuse and neglect. When working with youth in foster care, additional obstacles must be overcome: changing placements, overwhelmed substitute caregivers, caseworker turnover, complication with birth siblings and family, and communication difficulties with and within the child welfare system. Treating Trauma: Relationship-Based Psychotherapy with Children, Adolescents, and Young Adults presents a theoretically based and empirically supported framework for work with traumatized children, youth, and young adults who have spent time in foster care. It offers vivid examples of cases from the work of clinicians of A Home Within, a national non-profit focused on meeting the emotional needs of current and former foster youth. These nine case studies illustrate the vital role that relationships play in helping overcome the trauma of chronic, unexpected, and unexplained losses. They describe the work with clients, the collateral work, and also the therapists’ personal experiences of treating this vulnerable population. This work also explores the impact of secondary trauma on those working in an around the foster care system and addresses ways that therapists and others vulnerable to vicarious trauma can protect themselves, as well as their clients. In particular, three chapters examine the power of peer consultation in sustaining therapeutic work with vulnerable and traumatized populations. Methods of integrating evidence-based approaches into treatment of youth with multiple mental health problems and unavailable parents are discussed and explored. Essential elements of effective mental health interventions with traumatized foster youth are presented and illustrated.