Book excerpt: Bioactive Materials for Bone Regeneration summarizes research advances on the topic, including sections on the characteristics of biomaterial-induced microenvironments, interactions of bioactive materials with stem cells and tissues, and the immunomodulatory microenvironment induced by biomaterials and its effects on osteogenesis. As the regeneration of large-size bone tissue defects represents a significant clinical challenge, this book demonstrates how new biomaterials with specific chemical and physical characteristics may interact with the host and create a unique micro-environment that actively facilitates stem cell differentiation along a specific lineage, thus stimulating tissue regeneration.