Implementation Science is commonly described as the study of methods and approaches that promote the uptake and use of evidence-based interventions into routine practice and policymaking. In this issue ofJABFM, investigators share a wealth of new insights from the frontlines of Implementation Science in primary care: what it is, how we are doing it, and how it is advancing the evidence base of primary care. The breadth of implementation science in primary care is affirmed by the range of topics covered, from thought leader recommendations on future directions for the field, to reports on how best practices in policy and practice are shaping primary care implementation in the United States and Canada. There are also important updates on agents of primary care implementation themselves, such as practice facilitators, geriatric care teams, and family physicians interested in providing obstetric care. Other articles report on novel practice transformation efforts that advance health promotion and disease prevention, and innovative approaches to identifying and addressing social determinants of health in primary care practices and the communities they serve. The articles seem to generate as many new questions as they answer, and highlight the need for continued emphasis on advancing the science of implementation in primary health care.