Mold, a common term for fungal growth, is one of the most serious and underappreciated sources of damage to library and archival materials. This technical bulletin, funded by the Claneil Foundation and the William Penn Foundation, takes the reader step-by-step through managing a mold invasion in a collection. Topics covered include: health concerns, first response procedures, inactivation procedures, fungicides and fungistats, cleaning and disinfecting, prevention planning, general references, and services for recovery.