Fredrik Livheim, PhD, is a licensed clinical psychologist in the department of clinical neuroscience at the Karolinska Institutet in Stockholm, Sweden. He has trained more than 1,500 professionals in how to use acceptance and commitment therapy (ACT) in a group format to improve employees' mental health. His research focuses on the use of ACT to reduce stress and help people thrive. Frank W. Bond, PhD, is professor of psychology and management at Goldsmiths, University of London, where he is also director of the Institute of Management Studies. He has published widely in the areas of ACT and organizational behavior, and the processes that underpin peak performance and well-being in the workplace. He is currently using this interdisciplinary research to help the European Space Agency's manned mission to Mars in the next decade. Daniel Ek, MS, is a licensed clinical psychologist and mindfulness teacher, with professional experience in stress management. Ek treats patients with stress and chronic fatigue syndrome (CFS) on a daily basis, and trains professionals in how to use ACT in a group format to improve employees' mental health. Björn Skoggà rd Hedensjö, MS, is a science reporter and clinical psychologist.