Adverse Childhood Experiences: Using Evidence to Advance Research, Practice, Policy, and Prevention defines ACEs, provides a summary of the past 20 years of ACEs research, as well as provides guidance for the future directions for the field. It includes a review of the original ACEs Study, definitions of ACEs, and how ACEs are typically assessed. Other content includes a review of how ACEs are related to mental and physical health outcome, the neurodevelopmental mechanisms linking ACEs to psychopathology, sexual violence and sexual health outcomes, and violence across the lifespan. Important and contemporary issues in the field, like reconsidering how ACEs should be defined and assessed, the appropriateness of routine ACEs screening, thinking about ACEs from a public health and global perspective, strategies for preventing ACEs, understanding ACEs and trauma-informed care and resilience, and the importance of safe stable and nurturing environments for children are discussed. Adverse Childhood Experiences is a useful evidence-based resource for professionals working with children and families, including physicians, nurses, social workers, psychologists, lawyers, judges, as well as public health leaders, policy makers, and government delegates.