Book excerpt: What are skill-mix innovations and why are they relevant? This systemic analysis of health workforce skill-mix innovations provides an overview of the evidence and lessons for implementation across multiple countries. The authors focus on six core segments of health systems: health promotion and prevention, acute care, chronic care, long-term and palliative care, as well as access for vulnerable groups and people living in underserved areas. In addition, the book analyses the roles of educational systems, workforce planning and policy, and financing within individual countries' healthcare organisations from a cross-country perspective. Although implementing skill-mix changes may be prone to stakeholder opposition or other barriers, this book helps identify ways to steer the process. The authors ultimately determine what skill-mix innovations exist, who may benefit from the changes and how to implement these changes within health systems. This Open Access title is the sixth book in Cambridge's European Observatory on Health Systems and Policies series.