This chapter sets out the history, evolution of primary health care (PHC) and discusses its application to contemporary health systems. PHC is a whole-of-society approach to health that aims to maximize the level and distribution of health and well-being through three components: primary care and essential public health functions as the core of integrated health services; multisectoral policy and action; and empowered people and communities. The concept of PHC emerged in the 1960s but was formally codified in the 1978 Alma Ata Declaration. ‘Pragmatic’ reductivism and geopolitical transitions in ensuing decades saw original goals superseded by selective PHC. The World Health Report 2008 – Primary Health Care: Now More Than Ever renewed focus on PHC in the prevailing context of hospital-centrism, commercialization and fragmentation. Mounting evidence on effectiveness, equity and efficiency has made it clear that PHC is the path to achieve universal health coverage and the other health related Sustainable Development Goals. In 2018, governments renewed their commitment to strengthen primary health care in the Declaration of Astana.The WHO and UNICEF Operational Framework for PHC provides guidance for governments to translate these commitments into action.