"Optical Whispering Gallery Modes for Biosensing: From Physical Principles to Applications" is a comprehensive scientific exploration into the innovative use of optical whispering gallery modes (WGMs) in biosensing. Authored by leading experts, this book delves into the fundamental physics of WGMs and their transformative applications in detecting biomolecules. It bridges theoretical concepts with practical implementations, making it an essential read for researchers and professionals in photonics and biosensing. This volume not only illuminates cutting-edge technologies but also inspires advancements in biomedical diagnostics and environmental monitoring.