This book offers an overview of our current understanding of host defense peptides and their potential for clinical applications as well as some of the obstacles to this. The chapters, written by leading experts in the field, detail the number and diversity of host defense peptides, and discuss the therapeutic potential not only of antibacterial, but also of antifungal, antiviral, plant antimicrobial and anticancer host defense peptides. The authors provide new insights into their mechanisms of action and their immunomodulatory properties, and review recent advances in the design of novel therapeutic molecules. Lastly, their potential to prevent preterm births and Staphylococcus aureus infections is highlighted. The book is of interest to researchers, industry and clinicians alike.