Gives a basic overview of molds and mold growth, including life-cycle, growth, structure, reproduction, and nutrition. The wide variations in environmental tolerance of some species are discussed. The importance of microclimatic conditions is emphasized. The kinds of damage caused by fungi to archive and other materials is outlined. Fumigation is recommended as a precaution against adding infected items to a collection. A general prevention, i.e., control, is better than cure, i.e., chemical intervention. The advice of a microbiologist should be sought in cases of potential problems. -- AATA