Understanding and modifying health behaviors plays an important part in healthcare. The need to change behaviors applies across a range of health contexts, from individual interventions to the clinically-delivered management of chronic diseases and rehabilitation. Telehealth or virtual care technology offers many possible advantages here, including cost-efficiency, scalability, personalization, and automated high volume data collection and analysis, but success will depend on the effectiveness of the design, implementation and deployment of IT-based methods. This book, which forms part of the Global Telehealth series, includes papers presented at Global Telehealth 2019 (GT2019), a National Symposium on the topic of IT-based Methods for Health Behaviours held in Adelaide, Australia on 5 July 2019. The 10 papers selected for inclusion here comprise only full-paper, blind peer-reviewed contributions received for the symposium and the subsequent call for further contributions. Topics range from the scientific theory of health behavior change, through technological approaches to active ageing and the implementation of the 10,000 steps project, to a discussion of digital infrastructure for the storing & sharing of internet of things, wearables and app-based research study data. The book will be of interest to all researchers, managers and healthcare practitioners working to bring about positive changes in health behavior.