Book excerpt: Thr oughout the tropics there is a huge diversity in house design and use of building supplies based on centuries of indigenous ex- perience, customs, and availability of local resources for construc- tion. These differences in building style and materials affect the in- door conditions and comfor t of occupants, which in turn influence the occupants' exposure to certain infectious diseases. In this book the authors describe the architectural designs and materials of rural houses in two countries in Asia (Thailand, Philippines) and two in Africa (The Gambia, T anzania). They analyse the effect of design on the indoor climate and r elate these factors to health, notably the risk of mosquito-bor ne infectious diseases such as malaria. Based on their findings and a detailed understanding of local building styles, they describe a series of house modifications that could enhance comfor t whilst r educing health risks.