Many low – and low-middle income countries have pluralistic health systems, characterized by widespread and often highly segmented markets offering a diverse range of health-related goods and services. Out-of-pocket payment for health care averages more than 50% of all health spending in these countries, with non-state providers, both private and not-for-profit, typically providing the majority of outpatient curative care. If health services are to benefit the poor, it is essential to gain a detailed understanding of such markets that can both inform attitudes towards them and guide innovations that attempt to engage with them to improve health outcomes.