Abstract: Health care faces a persistent research-to-practice gap, with evidence-based innovations taking 17-20 years to reach routine clinical practice and less than 50% being successfully implemented. This introduction to the special section on implementation science presents 27 studies across two editions that demonstrate how systematic implementation science approaches can transform health care delivery. The first edition focuses on mental health services, examining evidence-based psychotherapy implementation, suicide prevention programs, and health equity initiatives across diverse populations including Veterans, incarcerated individuals, and marginalized communities. The second edition explores implementation frameworks, screening and assessment innovations, and approaches for vulnerable populations in complex health care settings. Key findings reveal that contextual adaptation, stakeholder engagement, and organizational support are critical for successful implementation. These articles provide empirical evidence that implementation science can significantly reduce the research-to-practice gap while improving intervention fidelity and sustainability, offering important insights for researchers, clinicians, administrators, and policymakers committed to evidence-based health care delivery.