A recent report by the United Nations Environment Programme (UNEP) showed that toxic chemical substances are responsible for 4.9 million deaths every year, i.e. 8.9 per cent of annual deaths. This report also highlights the fact that these figures are largely underestimated, given the significant knowledge gaps. Not only is the number of deaths and diseases caused by pollutants unknown, but most of the very large number of chemical substances in circulation have not been even minimally investigated for potential toxicity.1 The first four of these five books, and certain chapters of the last one, provide important contributions to the growing historical and sociological literature on toxicants and their governance. This literature sheds light on the paradox of the increasingly massive development of (potentially) toxic chemical substances for over a century: while knowledge—especially scientific knowledge — of these substances has been continually expanding, movements denouncing them have constantly evolved, and complex regulatory systems to prevent and improve the substances’ effects have been gradually developed. The books presented here provide insightful and detailed analysis of several major issues underpinning the literature on environmental chemicals. I shall present the five reviewed books focusing on four of those issues.