The U.S. faces a critical crisis in behavioral health and addiction care. Overburdened emergency rooms and primary care offices struggle with lengthy wait times, while workforce shortages and systemic barriers disproportionately impact marginalized communities. This has resulted in the criminal justice system becoming a de facto provider of mental health and addiction services. In 2024, Surgeon General Dr. Vivek Murthy declared a national epidemic of loneliness and isolation, exacerbated by the COVID-19 and opioid crises. His advisory underscores the importance of social connection, empathy, and belonging as vital components of well-being. Despite the urgent need, stigma surrounding mental health and substance use disorders persists, hindering access to care. Historically, training programs have underemphasized addiction and behavioral health education across medical and behavioral health disciplines. This book serves as a vital resource for interdisciplinary teams, highlighting the crucial role each profession plays in improving access to addiction and mental health care and reducing stigma. It advocates for a collaborative, relationship-centered approach, equipping clinicians and peers with the knowledge and skills to effectively address addiction and behavioral health within communities. Expertly written and reviewed, it offers up-to-date scientific and clinical information spanning a broad range of relevant topics.