HEI Communication 18, Household Air Pollution and Noncommunicable Disease, and the related Summary for Policy Makers are now available online. This communication provides a critical assessment of the state of the science examining the linkages between household air pollution formed by the burning of solid fuels and noncommunicable diseases. The report updates previous systematic reviews with the most recent studies. It answers fundamental questions on the scientific basis for estimating health burden and what the evidence suggests about the exposure reductions necessary to achieve improved health outcomes. The Summary for Policy Makers, based on Communication 18, presents the main conclusions about exposures to household air pollution and about its contribution to noncommunicable diseases globally and can be downloaded by clicking here.