Public health: who, what, and why?

There has been renewed concern about the state of public health in Canada, with several recent articles in this journal suggesting that the discipline of public health is under threat and that there has been a significant erosion of its core infrastructure. We strongly agree with the need for a well-resourced formal public health system and preservation of capacity to carry out core public health functions, while also positing a complementary narrative that emphasizes the possibility for a broad notion of public health to persevere and thrive in the face of these challenges. We consider what public health is, who public health is, and why public health exists, and suggest that the answers to these questions point to opportunities to strengthen the necessary interdisciplinary approaches that can best address current and future public health concerns.