This chapter outlines the dynamic context and multiple challenges of data sharing in the contemporary data ecosystem, specifically as it relates to healthcare. Here, we define ‘data sharing’ as the practice of sharing health-related data between a number of data controllers and processors. Data collected in this manner can come from the provision of health, clinical trials, observational studies, public health surveillance programs, and other health data collection methods. Several justifications for such sharing are introduced. Our main contention is that the regulatory environment today is an increasingly complex and rapidly evolving combination of norms and principles. To navigate it successfully requires careful analysis and judgment from all stakeholders across diverse fields of law and technology. The purpose of this volume, therefore, is to offer a series of case studies that integrate theoretical and practical perspectives and illustrate how to effectively navigate this rapidly evolving space.