Enrolment in ECEC settings has continued to rise over the last decade, partly because of the extension of the legal entitlement to a place in ECEC, and efforts to ensure free access, at least for some ages and selected population groups. This chapter is a general review of a range of socio-economic and other factors that may determine the need for ECEC, policy on ECEC, the kinds of ECEC provided and uptake of what is on offer. This chapter also includes a summary table with a full overview of the ECEC systems and provision across OECD countries.