This short piece introduces the special issue on environmental Kuznets curves (EKC) — the hypothesized 'inverted-U' relationship between levels of environmental degradation and per capita income. Although the analysis of EKC relationships has been a relatively recent phenomenon, there is widespread interest on the part of academics in this analysis, and on the part of policymakers in the resulting implications for environment and development. The following introduction outlines the contributions to EKC analysis of the papers comprising the special issue. This is done in two ways: first, the empirical results of the special issue papers are compared with previous analyses of the EKC relationships; and second, the additional insights offered by the special issue papers on EKCs are discussed.