This book explores the forefront of plasmonic probe design and their diverse applications, offering insights into the next wave of biosensing innovations. It includes contributions from international leaders on the integration of advanced molecular biochemistry, materials science, optoelectronics, and photonics methodologies to enhance the performance of SPR biosensors. In addition, it reviews the trajectories in developing flexible, reproducible, and efficient SERS substrates and presents future directions of biosensing.