This book presents the proceedings of the 21st Congress of the International Ergonomics Association (IEA 2021), held online on June 13-18, 2021. By highlighting the latest theories and models, as well as cutting-edge technologies and applications, and by combining findings from a range of disciplines including engineering, design, robotics, healthcare, management, computer science, human biology and behavioral science, it provides researchers and practitioners alike with a comprehensive, timely guide on human factors and ergonomics. It also offers an excellent source of innovative ideas to stimulate future discussions and developments aimed at applying knowledge and techniques to optimize system performance, while at the same time promoting the health, safety and wellbeing of individuals. The proceedings include papers from researchers and practitioners, scientists and physicians, institutional leaders, managers and policy makers that contribute to constructing the Human Factors and Ergonomics approach across a variety of methodologies, domains and productive sectors. This volume includes papers addressing the following topics: Activity Theories for Work Analysis and Design (ATWAD), Organisation design and management (ODAM), Ergonomic Work Analysis and Training (EWAT), Systems HF/E, HF/E Education and Professional Certification Development.