Book excerpt: Today, indoor mold and moisture, and their associated health effects, are a society-wide problem. The economic consequences of indoor mold and moisture are enormous. Their global dimension has been emphasized in several recent international publications, stressing that the most important means for avoiding adverse health effects is the prevention (or minimization) of persistent dampness and microbial growth on interior surfaces and in building structures. This book aims to describe the fundamentals of indoor mold growth as a prerequisite to tackle mold growth in the existing building stock as well as in future energy efficient buildings. It brings together different disciplinary points of view on indoor mold, ranging from physics and material science to microbiology and health sciences. The contents have been outlined according to three main issues: Fundamentals, particularly addressing the crucial roles of water and materials, Health, including a state-of-the-art description of the health-related effects of indoor molds, and Strategies, integrating remediation, prevention and policies.