This study focuses on the prevention and basic treatment of recurring mold growth in tropical climates where library-wide environmental control is not always possible. The introduction discusses major climatic groups; the effects of climate on specific materials found in library resources; and the range of options for modifying the environment. The next six chapters deal with the following topics: (1) the structure and nature of mold, and the environmental and nutritional factors in their growth and survival; (2) implications of the mold problem in the library setting; (3) prevention of mold growth in the library environment; (4) the traditional chemical approaches used to treat mold growth, i.e., fungicides and fumigation, and concerns in their use; (5) treatment options that might be used, based on an analysis of the problems and the nature of the material that is affected; and (6) a list of equipment and supplies for dealing with the problem. References to the literature cited appear at the end of each chapter. The final chapter provides a selected bibliography of 76 references. (CGD)