In this chapter I outline and endorse Evidence-Based Public Health (EBPH), noting that its basic principles have recently (at the time of writing) been largely ignored at important times. And further, that more careful consideration of these principles should lead to better public health outcomes. In order to fully grasp the context, I begin the chapter by looking at Evidence Based Medicine (EBM), the principles and clinical guidelines of which overlap significantly with EBPH (Mercuri and Upshur 2023). I demonstrate that recent (and poor) important public health decisions have been made that paid little attention to the tenets of EBPH—specifically those concerning the importance of context-dependency in policymaking. The lessons learned from these mistakes, I argue, could make a significant difference to public health decision making. I briefly outline and critique Stegenga’s (2018) “Master Argument”, which he claims demonstrates that our confidence in hypotheses concerning the effectiveness of medical interventions based on clinical trials should be low. Drawing on Stegenga, I end the chapter by considering the possibility that public health knowledge (that a public health intervention will work) is impossible. However, I tentatively conclude that an externalist approach to knowledge might provide a more positive outlook.