This book provides a comprehensive and up-to-date review of current understanding of periostin and its importance for human health and disease. Periostin is a secretory matricellular protein that has been revealed to play key roles in fibrillogenesis and cell migration, including metastasis of cancer cells. The production of periostin is upregulated during fibrotic responses and the mechanisms by which it promotes fibrosis have become a focus of interest owing to the potential clinical benefit to be derived from periostin blockade. In this book, readers will find coverage of all aspects, from the basic properties of periostin and its function as a scaffold for assembly of extracellular proteins through to its roles in bone and tissue regeneration, tumorigenesis, myocardial infarction, inflammatory and immune system disorders, and other diseases. Readers will also find the latest information on functions of periostin related to stemness and the application of periostin as a biomarker. It is hoped that the detailed knowledge of periostin and its pathobiological significance provided in this book will aid in the search for effective treatments for currently incurable diseases.