Lighting is of critical importance in all types of buildings. An adequate level and distribution of light is vital if visual tasks are to be carried out safely and effectively. Good lighting will also improve the internal environment and appearance of a building. The use of efficient lamps, ballasts and luminaries, with appropriate lighting controls, can provide the right visual environment, be energy efficient and cost effective. Part 2 of this Good Building Guide describes an internal domestic lighting scheme, exterior lighting and maintenance of luminaires and lamps, and provides a lighting design aide-memoire. It gives guidance on complying with Part L of the Building Regulations which requires that a proportion of lighting in new dwellings is energy efficient. Exterior lighting must be fitted with sufficient controls (e.g. daylight sensors, presence sensors) so that energy is not wasted and should minimise light pollution by directing light downwards as much as possible. 8 pages.