The goal of preventive conservation is to minimize unnecessary loss and damage to a collection. The risks to collections that result in loss and damage are numerous and diverse. Risk assessment is the identification and estimation of the magnitude of all such risks. Risk management is the development of a set of strategies to achieve the most cost-effective reduction in total risk to a collection. At present, the knowledge required to accurately determine the magnitude of many risks is not available. Nevertheless, adopting a risk assessment and management approach to preventive conservation provides a useful system for decision-making. Further, it provides a framework for organizing thoughts and information that improves communication between all museum staff involved with collections use, management, and care.