This manual describes installation practice considered satisfactory for the protection against lightning of a wide variety of structures, including those with explosive or highly flammable contents, and of mines. Factors governing the decision on the need or otherwise to provide protection in normal situations is discussed. A guide for personal safety during thunderstorms is given. The recommendations in this manual do not include the protection of power or communication systems or apparatus. the protection of aircraft is also excluded, although recommendations are given with respect of aircraft fuelling. The provisions of the manual should not be regarded as overriding statutory requirements but may be construed as working recommendations to be used in conjunction with any such legal requirements.