Lydia Kwak, PhD, is an associate professor and senior lecturer in worksite health promotion, head of the unit Intervention and Implementation Research for Worker Health and assistant study director of Doctoral Education at the Institute of Environmental Medicine, Karolinska Institutet, Sweden. Her research activities are related to intervention and implementation research in the field of worker health. She conducts research on how the health of the working population can be promoted at the workplace and how ill-health can be prevented. This research encompasses a broad range of research activities including those aimed at gaining knowledge on how effective interventions can be implemented into practice. She is experienced in conducting randomized controlled trials testing the effectiveness of different types of implementation strategies. She is currently conducting a randomized controlled trial in schools aimed at exploring mechanisms of change of a multifaceted implementation strategy for promoting mental health at the workplace.