The intelligent application of preservatives is aiding to combat the great waste of materials due to fungus attack. During World War II many efficient new fungicides were developed to protect cellulostic materials. These protective materials are now being incorporated in manufactured goods to increase their effective life and usefulness; a few of the more important methods of incorporating fungus resistance are described for such fields as paints, plastics, timber, electrical insulation, rope, and leather. New possibilities have now opened in providing even more powerful fungicides and fungistats for future use.