The benefits - environmental, economic and health - of ventilating buildings naturally, rather than mechanically, are becoming increasingly recognized. Approaches can be high- or low-tech but need to be a part of an integrated design approach. A range of technical barriers, such as building codes, fire regulations and acoustics, also need to be taken into account. This handbook describes the potential of natural ventilation, its appropriate use, the design and dimensioning methodologies, the need for an integrated design approach, and how to overcome barriers.